Development of the Sleeping Pills Ambivalence and Indecisiveness Scale-6 Among the General Population

Seockhoon Chung

doi:10.17241/smr.2026.03552

Sleep Med Res > Volume 17(2); 2026 > Article

Chung: Development of the Sleeping Pills Ambivalence and Indecisiveness Scale-6 Among the General Population

Original Article

Sleep Med Res 2026; 17(2): 129-138.

Published online: Jun 30, 2026

DOI: https://doi.org/10.17241/smr.2026.03552

Development of the Sleeping Pills Ambivalence and Indecisiveness Scale-6 Among the General Population

Seockhoon Chung, MD^1,²

¹Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea

²Life Care Center for Cancer Patient, Asan Medical Center Cancer Institute, Asan Medical Center, Seoul, Korea

Corresponding Author: Seockhoon Chung, MD, Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, 86 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea, Tel +82-2-3010-3411, Fax +82-2-485-8381, E-mail schung@amc.seoul.kr

Received Mar 17, 2026 Revised May 14, 2026 Accepted May 18, 2026

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background and Objective

The objective of this study was to develop a self-report rating scale to assess ambivalence toward taking sleep medication. Additionally, the study sought to examine whether intolerance of uncertainty and cognitive fusion are associated with this ambivalence.

Methods

A total of 550 participants from the general population were recruited for the study. Items designed to measure ambivalence toward taking sleep medication were collected and subjected to factor analysis, resulting in the development of a rating scale. The reliability of the scale was assessed through McDonald’s omega, while convergent validity was evaluated using the Insomnia Severity Index, Metacognitions Questionnaire for Insomnia-6, Adaptive Cognition and Behaviors about Sleep-6, Dysfunctional Beliefs and Attitudes about Sleep-6, Intolerance of Uncertainty Scale-12 (IUS-12), Cognitive Fusion Questionnaire (CFQ), and sleep indices such as the questionnaire version of the Discrepancy between desired time in Bed and desired total Sleep Time (DBSTq-2).

Results

The Sleeping Pills Ambivalence and Indecisiveness Scale-6 (SPAIS-6) was developed, showing strong internal consistency (McDonald’s omega=0.929) and good model fit (comparative fit index=0.979, Tucker-Lewis index=0.965, root mean square error of approximation= 0.102, standardized root mean square residual=0.021). Linear regression identified age and DBSTq-2, CFQ, and IUS-12 outcomes as significant associations. Mediation analysis indicated that intolerance of uncertainty and cognitive fusion partially mediated the association between DBSTq-2 outcomes and the SPAIS-6.

Conclusions

The SPAIS-6 is a reliable and valid instrument designed to assess ambivalence toward the use of sleep medication.

Key words: Insomnia, Sleep, Sedative-hypnotics, Cognition

INTRODUCTION

Sedatives/hypnotics are among the most commonly used pharmacological treatments for insomnia, frequently utilized in conjunction with Cognitive Behavioral Therapy for Insomnia (CBT-I) [1]. In the present study, the term “sleep medication” refers primarily to prescription sedatives and hypnotics, including benzodiazepine receptor agonists and related agents, rather than over-the-counter sleep aids. While the efficacy of sleep medication is well-established, patients often express concerns regarding their use, citing issues such as drug toxicity, perceived danger, addiction, tolerance, and apprehension about cognitive decline [2]. Although the adverse effects of sleep medication are extensively documented, attributing these concerns exclusively to it [3] may represent an overgeneralization. When employed appropriately and under medical supervision, sedatives/hypnotics can offer significant benefits to many individuals. The critical factor lies in balancing the advantages of improved sleep with the potential risks, ensuring that treatment plans are customized to address the specific needs and concerns of each patient.

In behavioral models such as Skinner’s operant conditioning [4], behavioral choices are determined by the binary outcomes of reinforcement and punishment [5]. However, from a cognitive-affective perspective, ambivalence disrupts this simplicity, introducing simultaneous positive and negative emotions during change or decision-making processes [6]. This emotional conflict often leads to resistance or stagnation. In motivational models such as the Transtheoretical Model known as Stages of Change model [7], or Motivational Interviewing [8], ambivalence is framed as a natural dilemma at each stage, requiring systematic exploration [6]. Similarly, ambivalence toward taking sleep medication appears to be a natural response among patients, potentially impacting their health outcomes. Specifically, such ambivalence may reduce medication adherence, undermine treatment engagement, impair patient–clinician communication regarding pharmacological options, and ultimately contribute to poorer insomnia outcomes. In addition, the media significantly influences public behavior, including decisions about the use of sleep medication. TV advertisements have increased medication usage, but warnings against the use of certain drugs were also featured in the media. The U.S. Food and Drug Administration (FDA) has issued recent warnings regarding several sleep medications [9]. While such regulatory measures are warranted, it should also be recognized that inappropriate use, insufficient patient education, and suboptimal prescribing practices may contribute to the adverse outcomes associated with sleep medication.

Adverse events associated with antihypertensive medications, such as orthostatic hypotension, chronic cough, and peripheral edema, are well-documented [10]; however, patients typically do not self-administer these medications. Oral hypoglycemic agents commonly cause gastrointestinal upset, hypoglycemia and weight gain, genitourinary infections, and edema [11]. However, patients only take them following prescription by a professional. One of the reasons why the prescribed dosages for sleep medication are often exceeded is that these medications are paradoxically perceived as less potent. The perception of excessive potency leading to concerns about difficulty waking up in the morning makes patients less likely to disregard the prescribed dosage. Patients frequently increase their intake of sleep medication, while physicians escalate the prescribed dosage, reflecting a lack of understanding regarding their appropriate and effective use. Practice guidelines stress that sleep medications should only be used for a short period following CBT-I [12]. The guidelines provide information on how long sleep medication treatment should last but lack guidance on how these medications should be used. Although it is commonly suggested that sleep medication should be taken 30 minutes before bedtime, the target get-out-of-bed time is not usually considered. Although the bedtime is normally selected depending on the latter, physicians and patients hardly ever discuss this issue [13–15]. This might contribute to a decrease in the effect of sleep medication.

Patients with insomnia disorder experience heightened stress in this context. They receive warnings from the media, physicians, and family members about the adverse effects of sleep medication, and yet have to struggle to sleep effectively even when they self-administer the medication. This creates ambivalence regarding the use of sleep medication, making them hesitate to take it and thereby perpetuating their sleep disturbances. Even those who decide to use it experience stress when deciding whether to continue or discontinue its use, often influenced by warnings from their neighbors. To effectively address insomnia, it is essential to establish appropriate guidelines for the use of sleep medication, ensuring that this use is restricted to individuals who genuinely require it.

The psychological characteristics of an individual may influence the ambivalence toward taking sleep medication. Ambivalence or indecisiveness may be related to intolerance of uncertainty. Although not specific to sleep medication use, a previous study concluded that ambivalence is a self-protective behavior, and that uncertainty may influence it [16]. Individuals with a high intolerance of uncertainty may interpret ambiguities as threats, which can increase anxiety and lead to avoidance, expressed as hesitation towards the use of medication. Thus, it can be posited that ambivalence towards taking sleep medication may be related to intolerance of uncertainty [17]. In addition, psychological inflexibility, which was reported to be related to insomnia [18], may play a role in ambivalence toward taking sleep medication. Thus, we hypothesized that cognitive fusion, a key factor for psychological inflexibility, may be related to ambivalence toward using sleep medication.

There is currently no available validated rating scale to assess ambivalence toward taking sleep medication. Several previously described rating scales such as the Dysfunctional Beliefs and Attitudes about Sleep-16 (DBAS-16) [19], the Adaptive Cognition and Behaviors about Sleep-6 (ACBS-6) [20], or the Sleeping Pills Receptivity and Involuntariness Scale-6 [21], include items regarding worries about taking sleep medication, or consider it in the binary terms of reinforcement and punishment characteristic of behavioral models. They do not measure the stress related to hesitancy experienced by the patient, which may exacerbate that caused by the sleep disturbances. To address this gap, the present study aimed to 1) develop and validate a brief self-report rating scale measuring ambivalence toward taking sleep medication, and 2) explore whether psychological characteristics such as intolerance of uncertainty and cognitive fusion are associated with this ambivalence.

METHODS

This study is part of the Asan-Sleeping Pills Ethology Ques-Tionnaires (A-SPEQTs) project, which aims to assess behaviors and attitudes toward the use of sleep medications. To develop the rating scale, an anonymous survey was conducted online among the general population by EMBRAIN in two phases: Sample I was recruited for exploratory factor analysis (EFA) from June 27 to July 3, 2025, and Sample II for confirmatory factor analysis (CFA) from July 5 to July 9, 2025. The survey form was designed to record information on demographic variables and clinical characteristics of the participants, as well as their responses to individual items included in the rating scales. The target sample size was determined to be 600 participants, calculated by allocating 50 individuals to each of the 12 cells representing the interaction of sex and six age groups according to the principles of the Central Limit Theorem. The company distributed 6,612 enrollment emails to 1.8 million panel members registered to the professional survey system of EMBRAIN. Of these, 1,536 participants accessed the link, and 664 completed the survey. To ensure sample validity, the fastest 5% of respondents in each quota (i.e., those with the shortest response times, suggesting insufficient engagement with the survey) were excluded. Participants with response times exceeding three times the overall average were excluded as well. Ultimately, 600 deidentified responses were collected for analysis. Of these, 550 responses were included in the final analysis after excluding those in which the stated bedtime and get-out-of-bed time were implausible (e.g., bedtime reported during daytime hours or get-out-of-bed time reported during late evening). The final sample comprised 276 participants in Sample I (for EFA) and 274 in Sample II (for CFA). The study protocol was approved by the Institutional Review Board of the Asan Medical Center (2025-0804). The study was conducted following the tenets of the declaration of Helsinki.

Measures

Development of a rating scale to evaluate ambivalence toward the use of sleep medication

We developed the scale through the following processes: 1) The objective of the scale was defined as measuring ambivalence towards taking sleep medication. 2) The literature was reviewed to collect relevant items, and clinical interviews with patients affected by insomnia were conducted to record their perspectives on ambivalence towards the use of sleep medication. From the 16 items initially recorded, a panel of three psychiatrists and two psychologists with expertise in sleep medicine reviewed the items and reached consensus through group discussion. The panel excluded redundant items with overlapping content, retaining six items that best represented distinct facets of ambivalence. Content validity was assessed through this expert consensus process; however, a formal content validity index (CVI) was not computed. Examples of excluded items with similar meanings such as “I feel that taking sleeping pills is necessary, but negative thoughts also come to mind” or “Taking sleeping pills helps me sleep, but I also worry about side effects.” A 0–10 Likert scale (0: strongly disagree, 10: strongly agree) was employed to ensure consistency with widely used measurement tools. 3) The EFA was performed using Sample I to reduce redundant items, and a penultimate scale was developed. 4) The CFA was performed using the developed scale to explore the construct validity. Internal consistency reliability was examined using McDonald’s omega. Convergent validity was examined using Pearson’s correlation coefficients and linear regression analysis. 5) The final scale was developed. In addition, we created an English version of the scale using translation and back-translation methods. Two native English speakers translated the Korean version into English, and two different native experts back-translated the English version of the scale without referring to the original scale. A different expert confirmed the accuracy of the translation by comparing the original Korean version and the back-translated Korean version and checking for discrepancies. Finally, a sleep medicine expert (S.C.) reviewed the final English version.

Insomnia Severity Index

The Insomnia Severity Index (ISI), a self-report measure developed to assess insomnia severity by Morin et al. [22], comprises seven items scored on a 5-point Likert scale (0–4). The total score ranges from 0 to 28, with higher scores indicating more severe insomnia. This study utilized the Korean version of the ISI validated by Chung et al. [23], which demonstrated good internal consistency (Cronbach’s α=0.839) in our total sample.

Metacognitions Questionnaire for Insomnia-6

The Metacognitions Questionnaire for Insomnia-6 (MCQI-6), is a short form derived by Lee et al. [24] from the original 60-item Metacognitions Questionnaire–Insomnia (MCQ-I) described by Waine et al. [25], which was developed to assess metacognitive beliefs in individuals with primary insomnia. It consists of six items designed to assess core dimensions of metacognitive beliefs related to insomnia, including intrusive thoughts and worry. Each item is rated on a 5-point Likert scale (0–4), with higher scores reflecting more maladaptive metacognitive beliefs associated with sleep disturbance. This study utilized the Korean version of the MCQI-6 validated by Lee et al. [24], which demonstrated good internal consistency (Cronbach’s α= 0.902) in our total sample.

ACBS-6

The ACBS-6, a self-report measure developed by Chung et al. [20], to assess sleep-related adaptive cognition, comprises six items scored on an 11-point Likert scale (0=strongly disagree to 10=strongly agree), with the final score calculated as the average of the six items. Higher scores indicate a higher level of sleep-related adaptive cognition. This study utilized the validated Korean version of the scale [20], which demonstrated good internal consistency (Cronbach’s α=0.730) in our total sample.

DBAS-6

DBAS-6 [26], a shortened version of the DBAS-16 [19], was developed by Jo et al. [26], to assess sleep-related cognition. It comprises six items scored on an 11-point Likert scale (0=strongly disagree to 10=strongly agree), with the final score calculated as the average of the six items. Higher scores indicate a higher level of sleep-related dysfunctional cognition. This study utilized the validated Korean version of the scale, which demonstrated good internal consistency (Cronbach’s α=0.774) in our total sample.

Intolerance of Uncertainty Scale-12

The Intolerance of Uncertainty Scale-12 (IUS-12) is a brief 12-item version [27], of the original 27-item IUS [28], designed to assess intolerance of uncertainty. It consists of 12 items that aim to assess degree of tolerance for uncertainty based on a 5-point Likert scale (1=“not at all characteristic of me” to 5=“entirely characteristic of me”), yielding a total score that ranges from 12 to 60, and with higher scores reflecting higher levels of intolerance to uncertainty. This study utilized the validated Korean version [29], which demonstrated good internal consistency (Cronbach’s α=0.924) in our total sample.

Cognitive Fusion Questionnaire

The Cognitive Fusion Questionnaire (CFQ) is a self-report measure developed by Gillanders et al. [30], and designed to assess levels of cognitive fusion. It consists of seven items scored on a 1–7 Likert scale (1=never true; 7=always true), with the total score derived from the sum of all seven items. The final score reflects higher levels of cognitive fusion. This study utilized the Korean version developed by Kim and Cho [31], which demonstrated good internal consistency (Cronbach’s α=0.955) in our total sample.

Sleep indices

Sleep indices, including time and duration variables, were assessed using the responses to specific questions provided by the participants. Time variables, including bedtime, sleep onset time, and get-out-of-bed time, were estimated based on responses to questions such as “What is your usual bedtime?,” “What is your usual time to fall asleep?,” and “What is your usual time to finally get out of bed in the morning?” [13]. Duration variables, including sleep onset latency and time in bed, were derived from time variables. The Discrepancy between desired time in Bed and desired total Sleep Time (DBST) index quantifies the mismatch between desired time in bed and desired total sleep time, calculated based on responses to questions such as “For how many hours per day do you wish to sleep?” and “From what time to what time do you wish to sleep?.” It represents the difference between the desired amount of sleeping and total sleep time [32]. In addition, we used the DBSTq-2 [33], a questionnaire-based version of the DBST index that comprises two items: 1) “Just 5 hours of sleep would feel like a dream come true,” and 2) “I want to fall asleep early in the evening and sleep well into the late morning.” Responses are scored on an 11-point Likert scale (0=strongly disagree to 10=strongly agree), with the final score calculated as the average of the two items.

Statistical Analysis

Statistical analysis involved EFA, conducted using Sample I, followed by CFA, conducted on Sample II using 1,000 bootstrap resamples. Normality was assessed through skewness and kurtosis within ±2, and sampling adequacy was evaluated using the Kaiser-Meyer-Olkin (KMO) measure and Bartlett’s sphericity test. Maximum likelihood estimation was employed in EFA to identify redundant items from six selected items, and a parallel analysis determined the number of factors based on eigenvalues from simulated and actual datasets. The 1,000-resample bootstrap CFA used diagonally weighted least squares estimation, with model fit assessed through standardized root mean square residual (SRMR ≤0.05), root mean square error of approximation (RMSEA ≤0.10), comparative fit index (CFI), and Tucker-Lewis index (TLI ≥0.90). Multi-group CFAs evaluated scale invariance across sex, insomnia status, hypnotics use, and psychiatric history.

Internal consistency was assessed using McDonald’s omega, and convergent validity was evaluated through Pearson’s correlation coefficients with previously described sleep indices and scales. Linear regression analysis was used to examine the contribution of sleep indices and psychological states to the new scale. Mediation analysis was conducted to examine whether the associations between sleep-related variables and ambivalence toward taking sleep medication were indirectly mediated through psychological variables, based on variables that were significant in the linear regression analysis. Outcomes distribution according to insomnia severity was visualized using ridgeline plots generated with the ggridges package (version 0.5.7) in R (version 4.5.1; R Foundation for Statistical Computing), and statistical analyses were conducted using JASP (version 0.14.1.0).

RESULTS

The study included a total of 550 individuals, with 276 in Sample I and 274 in Sample II. No significant differences between the two samples were observed in demographic variables, except for marital status and past psychiatric history, or in sleep indices or rating scales, except for get-out-of-bed time and DBSTq-2 outcome (Table 1).

Factor Analysis

Prior to conducting factor analysis, the normality of the responses to all six items was checked based on skewness and kurtosis ±2 in Sample I (Table 2). Sampling adequacy and data suitability were confirmed based on a value of 0.869 for the KMO measure and the significance of Bartlett’s sphericity (p<0.001). Parallel analysis revealed a single-factor structure of the developed scale with eigenvalues of 4.17, which surpassed the simulated 95th percentile eigenvalues of 1.21. Factor loadings for all items ranged between 0.71 and 0.85. In the CFA conducted using Sample II, the single-factor scale exhibited a strong fit, as indicated by the following fit indices: CFI=0.979, TLI=0.965, RMSEA= 0.102, and SRMR=0.021. Factor loadings for all items ranged between 0.76 and 0.90. The developed scale was named the Sleeping Pills Ambivalence and Indecisiveness Scale-6 (SPAIS-6). The multi-group CFA, utilizing configural, metric, and scale-invariant models, demonstrated that the single-factor model of the SPAIS-6 consistently measured ambivalence toward sleep medications across various demographic and clinical subgroups. Specifically, the outcome remained invariant across sex (CFI= 0.971, TLI=0.952, RMSEA=0.122, SRMR=0.001), insomnia status (yes or no; CFI=0.967, TLI=0.944, RMSEA=0.129, SRMR= 0.029), hypnotics use (yes or no; CFI=0.973, TLI=0.956, RMSEA= 0.116, SRMR=0.023), and prior psychiatric history (present or absent; CFI=0.970, TLI=0.950, RMSEA=0.124, SRMR= 0.026).

Reliability and Evidence Based on Relations to Other Variables

The McDonald’s omega coefficient of 0.929 for Sample II demonstrates that the single-factor structure of the SPAIS-6 scale exhibits strong internal consistency. Convergent validity of the SPAIS-6 was explored in relation to previously described sleep indices and rating scales. The SPAIS-6 outcomes for Sample II were significantly correlated with desired wake-up time (r= 0.166, p<0.001), DBSTq-2 outcome (r=0.310, p<0.001), ISI (r= 0.232, p<0.001), DBAS-6 outcome (r=0.221, p<0.001), MCQI-6 outcome (r=0.276, p<0.001), IUS-12 outcome (r=0.411, p< 0.001) and CFQ outcome (r=0.363, p<0.001) (Table 3).

Linear regression analysis with the enter method was performed using all samples (n=550) to identify variables associated with the SPAIS-6 outcome. The model explained 21.6% of the variance (adjusted R²=0.216, F=22.597, p<0.001). Variance inflation factors for all predictors were below 2.5, indicating no substantial multicollinearity. The results revealed that age (β= 0.159, p<0.001), DBSTq-2 outcome (β=0.150, p<0.001), CFQ outcome (β=0.120, p=0.041), and IUS-12 outcome (β=0.237, p<0.001) (Table 4) were significantly associated with the SPAIS-6 outcome. Mediation analysis was performed using 1,000 resample bootstrap with the significant variables from the linear regression analysis to examine whether psychological variables (intolerance of uncertainty and cognitive fusion) indirectly accounted for the association between DBSTq-2 outcomes and the SPAIS-6. The results showed that DBSTq-2 outcomes were directly associated with SPAIS-6 outcomes, and intolerance of uncertainty and cognitive fusion partially mediated this association (Table 5 and Fig. 1).

DISCUSSION

In this study, we developed a six-item, single-factor model to measure ambivalence towards taking sleep medication. Construct validity for SPAIS-6 was excellent based on model fitting, and internal consistency reliability based on McDonald’s omega was good. Convergent validity was good based on the correlation with the ISI, DBAS-6, and MCQI-6. Linear regression analysis revealed that DBSTq-2 outcomes, intolerance of uncertainty, and cognitive fusion were significantly associated with the SPAIS-6. Mediation analysis indicated that intolerance of uncertainty and cognitive fusion partially mediated the association between DBSTq-2 outcomes and SPAIS-6.

Ambivalence toward taking sleep medication may be assessed in relation to the balance between reinforcement (beneficial effects of medication) and punishment (adverse effects of medication). Assessing both factors through single-item measures may lead to the formulation of items reflecting this ambivalence, such as “I want to take it, but I am afraid of it,” and to the development of numerous items that were similar in both design and content. This was the rationale for excluding items prior to conducting factor analysis on the collected data. When EFA is conducted on all recorded items, similar items tend to cluster into the same factor, resulting in a large, redundant rating scale that lacks utility. Group discussions with psychiatrists and psychologists determined that the selection of six representative items was essential to prevent redundancy in the scale.

Ambivalence toward taking sleep medication may be linked to thoughts regarding anticipated effects and to concerns about potential adverse outcomes. Thus, rating scales capable of measuring them may be effective for exploring the convergent validity of the SPAIS-6, which is warranted in further studies. On the other hand, a significant correlation was identified in this study between the SPAIS-6 and DBAS-6/MCQI-6. However, the ACBS-6 was not correlated with the SPAIS-6 in the correlation analysis, and DBAS-6/MCQI-6 were not identified as contributing factors to the SPAIS-6 in the linear regression analysis. Thus, the ridgeline plot was generated based on the distribution of the ACBS-6, DBAS-6, and SPAIS-6 scales in relation to insomnia severity (Fig. 2). This suggests potential associations among the three rating scales that may vary according to insomnia severity, warranting further investigation. Interestingly, the ISI was not identified as a contributing factor for the SPAIS-6, but DBSTq-2 outcomes were. Although this may be the consequence of the interaction between two similar scales in one model, there is a possibility that the DBSTq-2 may differ from the ISI in terms of its relationship with ambivalence. The DBSTq-2 consists of two items that measure opposing aspects of sleep duration: one item reflects agreement with shorter sleep time duration when this is highly desired by the patient, while the other reflects agreement with an implicitly longer sleep time duration. It may be related to the ambivalent attitude in this study. Of course, further research is needed to explore whether the discrepancy between these two related but different variables may be one of the factors affecting ambivalence towards taking sleep medication.

In this study, intolerance of uncertainty and cognitive fusion partially mediated the association between DBSTq-2 outcomes and SPAIS-6. Intolerance of uncertainty is characterized by a tendency to react negatively to ambiguous situations [34], whereas cognitive fusion amplifies psychological inflexibility by reinforcing rigid adherence to conceptualized narratives [35]. Intolerance of uncertainty amplifies cognitive biases, heightening the perception of threats related to uncertain outcomes such as potential side effects of medication, risk of dependency, or variable efficacy. This process fosters conflicting attitudes, a desire for symptom relief weighed against apprehension of harm that manifests as motivational indecision. Patients oscillate between endorsement and avoidance, reflecting psychological inflexibility, where experiential avoidance perpetuates sleep disturbances despite available interventions. On the other hand, intolerance of uncertainty perpetuates persistent worry and rumination, which are core transdiagnostic factors in the maintenance of insomnia. This occurs by exacerbating dysfunctional beliefs about sleep and mediating pathways between anxiety or depression and reduced treatment response. Cognitive fusion interferes with adherence to sleep medicine by limiting behavioral flexibility. Rigid beliefs about hypnotics perpetuate avoidance, mirroring the patterns observed in the cycles of worry driven by intolerance of uncertainty. Further research using longitudinal designs is warranted to explore whether ambivalence toward taking sleep medication plays a mediating role in the relationship between psychological characteristics and insomnia severity. It should be noted that the present mediation findings are based on cross-sectional data and should be interpreted as indirect associations rather than evidence of causal mediation. The SPAIS-6 may also be relevant within the context of the Multimodal Optimized Treatment for Insomnia Framework (MOTIF), which categorizes patients with insomnia based on their ability to sleep without hypnotics and their attitudes toward hypnotic use [36]. In the MOTIF feasibility study [36], the subgroup unable to sleep without hypnotics but with an unfavorable attitude toward taking them had the lowest rate of hypnotic use (6.1%), suggesting that unresolved ambivalence may leave sleep disturbances untreated. The SPAIS-6 could provide a more comprehensive and validated measure of this attitudinal dimension compared to a single-item question, potentially facilitating more precise patient categorization and treatment planning within the MOTIF framework.

There are several limitations in this study. First, the scale was developed using an online survey, and this approach may introduce certain biases, warranting cautious interpretation of the results. Moreover, as participants anonymously completed self-report rating scales, additional sources of potential bias could not be ruled out. Second, ambivalence toward taking sleep medication may vary depending on whether participants were taking such medication at the time of the survey or not. In this study, the SPAIS-6 was validated within the general population. However, further validation is necessary among patients with insomnia, particularly those who are taking sleep medication. Therefore, its direct applicability to clinical populations should be interpreted with caution until validated in clinical samples. Clinically, the SPAIS-6 may have potential utility in assessing medication-related concerns, facilitating shared decision-making between patients and clinicians, monitoring treatment adherence, and guiding patient education regarding sleep medication. Third, although the RMSEA value (0.102) slightly exceeded the commonly accepted threshold of 0.08, other fit indices (CFI =0.979, TLI=0.965, SRMR=0.021) indicated good to excellent model fit. The elevated RMSEA may be attributable to the small number of degrees of freedom inherent in a single-factor model with only six items, which is a known phenomenon in which RMSEA tends to be inflated in models with low degrees of freedom. Fourth, a formal CVI was not computed during the item reduction process; content validity was assessed through expert consensus discussion only. Fifth, most sleep indices were not associated with the SPAIS-6, suggesting that subjective reporting of sleep indices might have influenced the results. Objective measures could provide further clarity on whether ambivalence toward taking sleep medication is genuinely unrelated to these indices.

In conclusion, the SPAIS-6 is a reliable and valid self-report rating scale designed to measure ambivalence towards taking sleep medication. Investigating the ambivalence experienced by patients with insomnia using this scale may provide valuable insights into their behavior and its impact on their sleep problems, potentially contributing to the improvement of their insomnia symptoms. However, as the present validation was conducted in a general population sample, further studies in clinical populations are warranted to confirm its applicability in patients with insomnia who are actively prescribed sleep medication.

NOTES

Availability of Data and Material

Data will be made available by the author upon reasonable request.

Conflicts of Interest

Seockhoon Chung, a contributing editor of the Sleep Medicine Research, was not involved in the editorial evaluation or decision to publish this article.

Funding Statement

None

Acknowledgements

None

REFERENCES

1. Morin CM. Cognitive-behavioral approaches to the treatment of insomnia. J Clin Psychiatry 2004;65(Suppl 16):33-40.

2. Vermeeren A, Coenen AM. Effects of the use of hypnotics on cognition. Prog Brain Res 2011;190:89-103.

3. Verster JC, Veldhuijzen DS, Patat A, Olivier B, Volkerts ER. Hypnotics and driving safety: meta-analyses of randomized controlled trials applying the on-the-road driving test. Curr Drug Saf 2006;1:63-71.

4. Morris EK, Smith NG, Altus DEBF. Skinner’s contributions to applied behavior analysis. Behav Anal 2005;28:99-131.

5. Scott HK, Jain A, Cogburn M. Behavior Modification. StatPearls [Internet]. Treasure Island: StatPearls Publishing; 2026 accessed 2026 February 17. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459285/.

6. Braga C, Ribeiro AP, Sousa I, Gonçalves MM. Ambivalence predicts symptomatology in cognitive-behavioral and narrative therapies: an exploratory study. Front Psychol 2019;10:1244.

7. Prochaska JO, Velicer WF. The transtheoretical model of health behavior change. Am J Health Promot 1997;12:38-48.

8. Rubak S, Sandbaek A, Lauritzen T, Christensen B. Motivational interviewing: a systematic review and meta-analysis. Br J Gen Pract 2005;55:305-12.

9. American Academy of Sleep Medicine. FDA requires new warning for several insomnia medications [Internet]. Darien: American Academy of Sleep Medicine; 2019 accessed 2026 February 17. Available from: https://aasm.org/fda-new-warning-insomnia-medications/.

10. Albasri A, Hattle M, Koshiaris C, Dunnigan A, Paxton B, Fox SE, et al. Association between antihypertensive treatment and adverse events: systematic review and meta-analysis. BMJ 2021;372:n189.

11. Hamnvik OP, McMahon GT. Balancing risk and benefit with oral hypoglycemic drugs. Mt Sinai J Med 2009;76:234-43.

12. Sateia MJ, Buysse DJ, Krystal AD, Neubauer DN, Heald JL. Clinical practice guideline for the pharmacologic treatment of chronic insomnia in adults: an American Academy of Sleep Medicine clinical practice guideline. J Clin Sleep Med 2017;13:307-49.

13. Chung S, Youn S, Yi K, Park B, Lee S. Sleeping pill administration time and patient subjective satisfaction. J Clin Sleep Med 2016;12:57-62.

14. Youn S, Choi B, Lee S, Kim C, Chung S. Time to take sleeping pills and subjective satisfaction among cancer patients. Psychiatry Investig 2020;17:249-55.

15. Youn S, Hann CWC, Park B, Lee S, Yi K, Chung S. The effects of the new guidance ‘take your sleeping pills 7 h before your wake-up time’: a pilot study. Sleep Biol Rhythms 2016;14:397-404.

16. Reich T, Wheeler SC. The good and bad of ambivalence: desiring ambivalence under outcome uncertainty. J Pers Soc Psychol 2016;110:493-508.

17. Morriss J, Goh K, Hirsch CR, Dodd HF. Intolerance of uncertainty heightens negative emotional states and dampens positive emotional states. Front Psychiatry 2023;14:1147970.

18. El Rafihi-Ferreira R, Linares IMP, Paulos-Guarnieri L, Zakiei A. Psychological inflexibility as a predictor associated with insomnia. J Sleep Res 2024;33:e14232.

19. Morin CM, Vallières A, Ivers H. Dysfunctional beliefs and attitudes about sleep (DBAS): validation of a brief version (DBAS-16). Sleep 2007;30:1547-54.

20. Chung S, Yoo S, Suh S. Development of the Adaptive Cognition and Behaviors about Sleep-6 (ACBS-6) for sleep-related conditions or behaviors diminishing insomnia severity. Sleep Med 2025;134:106703.

21. Chung S, Shahrier MA. Development of the Sleeping Pills Receptivity and Involuntariness Scale-6 (SPRIS-6) to assess acceptance of hypnotics use. Nat Sci Sleep 2025;17:2309-19.

22. Morin CM, Belleville G, Bélanger L, Ivers H. The Insomnia Severity Index: psychometric indicators to detect insomnia cases and evaluate treatment response. Sleep 2011;34:601-8.

23. Chung S, Ahmed O, Cho E, Bang YR, Ahn J, Choi H, et al. Psychometric properties of the Insomnia Severity Index and its comparison with the shortened versions among the general population. Psychiatry Investig 2024;21:9-17.

24. Lee J, Ha S, Ahmed O, Cho IK, Lee D, Kim K, et al. Validation of the Korean version of the Metacognitions Questionnaire-Insomnia (MCQ-I) scale and development of shortened versions using the random forest approach. Sleep Med 2022;98:53-61.

25. Waine J, Broomfield NM, Banham S, Espie CA. Metacognitive beliefs in primary insomnia: developing and validating the Metacognitions Questionnaire--Insomnia (MCQ-I). J Behav Ther Exp Psychiatry 2009;40:15-23.

26. Jo H, Jeon HJ, Ahn J, Jeon S, Kim JK, Chung S. Dysfunctional Beliefs and Attitudes about Sleep-6 (DBAS-6): data-driven shortened version from a machine learning approach. Sleep Med 2024;119:312-8.

27. Carleton RN, Norton MA, Asmundson GJ. Fearing the unknown: a short version of the Intolerance of Uncertainty Scale. J Anxiety Disord 2007;21:105-17.

28. Birrell J, Meares K, Wilkinson A, Freeston M. Toward a definition of intolerance of uncertainty: a review of factor analytical studies of the Intolerance of Uncertainty Scale. Clin Psychol Rev 2011;31:1198-208.

29. Kim SH. The relationship of fear of negative and positive evaluation, intolerance of uncertainty, and social anxiety [master’s thesis]. Seoul: Ehwa University; 2010.

30. Gillanders DT, Bolderston H, Bond FW, Dempster M, Flaxman PE, Campbell L, et al. The development and initial validation of the cognitive fusion questionnaire. Behav Ther 2014;45:83-101.

31. Kim BO, Cho S. Psychometric properties of a Korean version of the cognitive fusion questionnaire. Soc Behav Pers 2015;43:1715-23.

32. Lee J, Cho IK, Kim K, Kim C, Park CHK, Yi K, et al. Discrepancy between desired time in bed and desired total sleep time, insomnia, depression, and dysfunctional beliefs about sleep among the general population. Psychiatry Investig 2022;19:281-8.

33. Chung S, Jeon S. Development of Sleep medications MYTH-understanding (SMYTH) and Sleep Medications Overexpectation of REsponses (SMORE) among the general population. Sleep Breath 2026;30:153.

34. Appel H, Gerlach AL. Intolerance of uncertainty causally affects indecisiveness. Br J Clin Psychol 2025;64:806-16.

35. Lee SW, Lee SJ, Choi M. Psychological inflexibility, cognitive fusion, and thought-action fusion as a transdiagnostic construct: direct comparisons among major depressive disorder, obsessive-compulsive disorder, and healthy controls. Psychiatry Investig 2025;22:93-101.

36. Chung S. Exploring the characteristics of individuals grouped based on the multimodal optimized treatment for insomnia framework among individuals complaining of insomnia. Psychiatry Investig 2026;23:396-408.

Fig. 1

Mediation model showing the pathway from the effect of DBSTq-2 (independent variable) on ambivalence toward taking sleep medication (outcome) through cognitive fusion and intolerance of uncertainty (mediator). **p<0.01. DBSTq-2, questionnaire version of the Discrepancy between desired time in Bed and desired total Sleep Time.

Fig. 2

Ridgeline plot for the distribution of ACBS-6, DBAS-6, and SPAIS-6 outcomes according to insomnia severity. ACBS-6, Adaptive Cognition and Behaviors about Sleep-6; DBAS-6, Dysfunctional Beliefs and Attitudes about Sleep-6; SPAIS-6, Sleeping Pills Ambivalence and Indecisiveness Scale-6.

Table 1

Baseline demographics of the participants (n=550)

Variable	Sample I (n=276)	Sample II (n=274)	p-value
Male	141 (51.1)	142 (51.8)	0.863
Age (yr)	49.8±16.3	49.5±16.4	0.846
Marital status			0.026
Unmarried	84 (30.4)	77 (28.1)
Married, without kids	10 (3.6)	25 (9.1)
Married, with kids	161 (58.3)	162 (59.1)
Others	21 (7.7)	10 (3.7)
Psychiatric history
Past psychiatric history (yes)	78 (28.3)	57 (20.8)	0.042
Are you currently experiencing insomnia? (yes)	70 (25.4)	61 (22.3)	0.394
Difficulty falling asleep	18 of 70 (25.7)	17 of 61 (27.9)	0.837
Frequent waking	34 of 70 (48.8)	31 of 61 (50.8)
Both	18 of 70 (25.7)	13 of 61 (21.3)
Are you currently taking sleeping pills? (yes)	22 of 70 (31.4)	24 of 61 (39.3)	0.739
Sleep indices
Bedtime	10:55±1:49 pm	10:44±2:00 pm	0.254
Sleep onset time	11:20±1:49 pm	10:57±2:30 pm	0.066
Get-out-of-bed time	6:46±0:58 am	6:34±1:01 am	0.030
Sleep onset latency (SOL), hr	0.4±1.4	0.2±1.7	0.150
Time in bed (TIB), hr	7.5±1.1	7.4±1.1	0.343
Time in bed during 24 hours (TIB/d), hr	7.7±2.1	7.6±2.2	0.671
DBST index
Desired total sleep time (dTST), hr	7.2±1.1	7.3±1.3	0.244
Desired bedtime	10:49±0:48 pm	10:48±0:55 pm	0.647
Desired wake-up time	6:43±0:55 am	6:46±1:04 am	0.443
Desired time in bed (dTIB), hr	8.0±1.1	8.1±1.3	0.410
DBST index	0.8±1.3	0.7±1.6	0.563
DBSTq-2	4.6±2.5	4.3±2.4	0.034
Measures
Insomnia Severity Index (ISI)	10.0±5.3	9.6±5.3	0.310
Dysfunctional Beliefs and Attitudes about Sleep-6 (DBAS-6)	4.4±1.7	4.2±1.8	0.363
Metacognitions Questionnaire for Insomnia-6 (MCQI-6)	12.8±4.4	12.7±4.2	0.762
Adaptive Cognition and Behaviors about Sleep-6 (ACBS-6)	4.0±1.9	4.0±1.7	0.943
Intolerance of Uncertainty Scale-12 (IUS-12)	30.6±6.9	30.9±7.5	0.645
Cognitive Fusion Questionnaire (CFQ)	23.8±10.4	24.1±9.8	0.724

Values are presented as number (%) or mean±standard deviation.

DBST, Discrepancy between desired time in Bed and desired total Sleep Time; DBSTq-2, questionnaire version of the DBST.

Table 2

Properties of individual items of scale

Item	Mean*	SD*	Skewness*	Kurtosis*	EFA factor loading*	CFA factor loading†
1. Sleeping pills help me get a good night’s sleep, but I grapple with the possibility of becoming dependent on them.	6.11	2.87	−0.59	−0.43	0.71	0.79
2. Sleeping pills help me fall asleep quickly, but I grapple with whether they may be harmful in the long run.	7.03	2.58	−0.97	−0.50	0.77	0.85
3. Sleeping pills help me sleep, but it’s uncomfortable when family and others around me say things that show their concerns.	5.91	2.82	−0.51	−0.52	0.83	0.76
4. I feel I need to take sleeping pills, but I’m afraid of the social misconceptions surrounding them.	5.73	2.67	−0.41	−0.31	0.77	0.77
5. Taking sleeping pills is my choice, but I grapple with whether it’s the right solution.	6.43	2.64	−0.65	−0.01	0.85	0.90
6. Sleeping pills are helpful, but I’m afraid I won’t be able to fall asleep without them in the future.	6.40	2.86	−0.66	−0.30	0.85	0.88

^* Among Sample I (n=276);

^† Among Sample II (n=274).

SD, standard deviation; EFA, exploratory factor analysis; CFA, confirmatory factor analysis.

Table 3

Correlation analysis of clinical variables with the single-factor model of SPAIS-6 (Sample II, n=274)

Variable	SPAIS-6 total score
Age	0.114
Sleep indices
Bedtime	−0.003
Sleep onset time	−0.001
Get-out-of-bed time	0.061
Sleep onset latency (SOL)	0.004
Time in bed (TIB)	0.082
Time in bed during 24 hours (TIB/d)	0.056
DBST index
Desired total sleep time	−0.007
Desired bedtime	0.038
Desired wake-up time	0.166**
Desired time in bed	0.117
DBST index	0.104
DBSTq-2	0.310**
Rating scales scores
Insomnia Severity Index	0.232**
Dysfunctional Beliefs and Attitudes about Sleep-6	0.221**
Metacognitions Questionnaire for Insomnia-6	0.276**
Adaptive Cognition and Behavior about Sleep-6	0.067
Intolerance of Uncertainty Scale-12	0.411**
Cognitive Fusion Questionnaire	0.363**

^** p<0.01.

SPAIS-6, Sleeping Pills Ambivalence and Indecisiveness Scale-6; DBST, Discrepancy between desired time in Bed and desired total Sleep Time; DBSTq-2, questionnaire version of the DBST.

Table 4

Linear regression analysis (all sample, n=550)

Dependent variables	Included parameters	β	p-value	Adjusted R²	F, p-value
SPAIS-6	Age	0.159	<0.001	0.216	F=22.597, p<0.001
	DBSTq-2	0.150	<0.001
	ISI	0.030	0.558
	DBAS-6	0.020	0.685
	MCQI-6	0.038	0.476
	CFQ	0.120	0.041
	IUS-12	0.237	<0.001

SPAIS-6, Sleeping Pills Ambivalence and Indecisiveness Scale-6; DBSTq-2, questionnaire version of the Discrepancy between desired time in Bed and desired total Sleep Time; ISI, Insomnia Severity Index; DBAS-6, Dysfunctional Beliefs and Attitudes about Sleep-6; MCQI-6, Metacognitions Questionnaire for Insomnia-6; CFQ, Cognitive Fusion Questionnaire; IUS-12, Intolerance of Uncertainty Scale-12.

Table 5

Mediation analysis (all sample, n=550)

Effect	Standardized estimate	Z-value	p-value	95% CI
Direct effect:
DBSTq-2 → SPAIS-6	0.072	4.270	<0.001	0.039 to 0.105
Indirect effect:
DBSTq-2 → CFQ → SPAIS-6	0.021	2.559	0.011	0.005 to 0.037
DBSTq-2 → IUS-12 → SPAIS-6	0.030	4.100	<0.001	0.016 to 0.045
Component
DBSTq-2 → CFQ	0.154	9.553	<0.001	0.123 to 0.186
CFQ → SPAIS-6	0.137	2.658	0.008	0.036 to 0.237
DBSTq-2 → IUS-12	0.124	7.480	<0.001	0.092 to 0.157
IUS-12 → SPAIS-6	0.245	4.880	<0.001	0.147 to 0.434
Total effect:
DBSTq-2 → SPAIS-6	0.124	7.450	<0.001	0.091 to 0.156

CI, confidence interval; DBSTq-2, questionnaire version of the Discrepancy between time in Bed and desired total Sleep Time; SPAIS-6, Sleeping Pills Ambivalence and Indecisiveness Scale-6; CFQ, Cognitive Fusion Questionnaire; IUS-12, Intolerance of Uncertainty Scale-12.