Introduction

Insomnia includes both nighttime and daytime symptoms, affecting approximately 30% of adults who report experiencing symptoms, with 10% meeting the diagnostic criteria for insomnia disorder1. Despite its prevalence, the underlying mechanisms of insomnia remain poorly understood. One of the most influential models of insomnia is the “3P” model, developed by Spielman [see 2]. According to this model, predisposing, precipitating, and perpetuating factors each play distinct roles in the development and persistence of insomnia. Predisposing factors increase vulnerability to insomnia, precipitating factors trigger acute episodes, and perpetuating factors, including behaviors and cognitions, contribute to the maintenance of sleep disturbances even after the initial trigger has been removed2.

Chronotype and insomnia

One characteristic that is closely associated with insomnia is chronotype, which is usually defined as morningness - eveningness and refers to differences in preferences for sleep and wake times. These preferences are influenced by both endogenous circadian clocks, regulating physiological and behavioral rhythms, and exogenous factors (e.g., work schedules)3. Morning types typically wake up and go to bed earlier, excelling in the morning, whereas evening types prefer later bedtimes and wake times, performing better in the afternoon or evening.

These variations in diurnal preferences for activity and sleep have been differentially related to several psychological health problems4. Additionally, chronotype is shown to be a strong predictor of sleep problems5. Previous research suggests a high prevalence of insomnia symptoms among individuals with an evening preference6,7. Currently, a longitudinal study conducted by Cheung et al.8 showed that a later chronotype predicts increased insomnia symptoms over time. Similarly, a review and meta-analysis by Zhao et al.9 which examined the relationship between chronotype and insomnia, found that individuals with an evening chronotype are more likely to report insomnia symptoms compared with those with morning chronotypes. Thus, an evening chronotype may serve as a risk and predisposing factor for insomnia due to misalignment with one’s circadian phase, leading to sleep difficulties10.

Chronotype and bedtime procrastination

Previous studies have found that individuals with evening chronotype report higher levels of bedtime procrastination11 which is defined as not going to bed at the desired time even though no external conditions prevent it12. According to authors, bedtime procrastination requires a needless, voluntary delay that occurs despite foreseeable negative consequences. Initial studies have confirmed that this particular form of procrastination is associated both with general procrastination and with self-regulation13. Further research proved that bedtime procrastination may result not only from the individual’s low self-regulation skills but also from the chronotype14. Specifically, individuals with an evening chronotype were more likely than those with a morning chronotype to delay going to bed. They also reported lower levels of autonomous motivation to regulate their sleep behaviors. This reduced motivation may contribute to a greater tendency to postpone bedtime and, consequently, to a higher frequency of insufficient sleep. Kroese et al.15 proposed that a late chronotype acts as a biological predisposition to increased bedtime procrastination, with evening chronotypes requiring more self-regulatory resources to adhere to their planned bedtimes. Similarly, a meta-analysis provided by Hill et al.16 revealed that bedtime procrastination had a moderate positive association with evening chronotype. Moreover, circadian misalignment—particularly common in evening chronotypes whose biological rhythms conflict with socially imposed schedules—can impair executive functions and self-control17. These impairments manifest in weaker reward-related inhibitory control18, greater difficulty regulating behavioral impulses19 and reduced self-regulatory capacity to adhere to planned bedtimes12. Thus, circadian preferences, previously associated with emotional dysregulation, impulsive behavior, and increased reward sensitivity20 may influence the risk of engaging in procrastination21. Finally, recent longitudinal evidence has also shown significant associations between chronotype and bedtime procrastination, with evening types reporting greater bedtime procrastination across a two-week assessment period22. Taken together, these findings suggest that chronotype may be a crucial driver of bedtime procrastination.

Bedtime procrastination and Insomnia

Finally, an increasing number of studies have suggested that bedtime procrastination is linked to insomnia22,23. A study by Alshammari et al.24 revealed that individuals with medium and high levels of bedtime procrastination were twice as likely to report insomnia compared to those with low levels. Thus, bedtime procrastination may be regarded as a significant sleep-related behavior that contributes to the perpetuation of insomnia. Moreover, recent findings by Zhu et al.25 showed that bedtime procrastination partially mediates the relationship between chronotype and sleep quality, as measured by the Pittsburgh Sleep Quality Index (PSQI), although this measure is not specific to insomnia. To date, however, the potential pathway from chronotype to insomnia through bedtime procrastination has not been examined.

Therefore, there is strong theoretical and empirical support for the hypothesis that bedtime procrastination mediates the relationship between chronotype and insomnia symptoms. Evening types consistently demonstrate a greater tendency to delay intended bedtimes compared to morning types14. Bedtime procrastination, in turn, has been associated with shorter sleep duration, poorer sleep quality, and increased difficulties with sleep onset, indicating its direct contribution to insomnia-related outcomes22. Moreover, meta-analytic evidence indicates that an evening chronotype is associated with an increased risk of insomnia9 however, the mechanisms underlying this relationship are not fully explained by chronotype alone. Although a study by Zhu et al.25 demonstrated that bedtime procrastination partially mediated the relationship between chronotype and sleep quality, further research is needed to empirically verify the potential mediating role of bedtime procrastination in the association between chronotype and insomnia. Chronotype may predispose individuals to engage in bedtime procrastination, which, in turn, may contribute to the development of insomnia symptoms. Accordingly, the present study examines whether bedtime procrastination might serve as a mediator in the association between chronotype and insomnia.

Participants and methods

Participants and procedure

An anonymous online questionnaire was distributed via mailing lists and social media, with participants encouraged to share the link with other adults to enhance sample diversity. A total of 671 adults participated in the study, including 191 men (Mage = 28.56, SD = 12.08), 473 women (Mage = 31.89, SD = 12.61), and 7 individuals identifying as other (Mage = 30.71, SD = 16.08), with a mean age of 30.72 years (SD = 12.54). The required sample size was determined assuming a 95% confidence level, a population proportion of 0.5, and a maximum margin of error of 4%. Participation was voluntary and uncompensated. All participants provided informed consent prior to taking part in the study, after receiving detailed information about its purpose, procedures, and their right to withdraw at any time. The study was conducted in accordance with the ethical standards of the Declaration of Helsinki and was approved by the Research Ethics Committee of the Faculty of Management and Social Communication at Jagiellonian University.

Measures

Chronotype

The Chronotype Questionnaire26 is a validated Polish version comprising two scales that assess subjective daily activity rhythms: Subjective Phase, measured by the Morningness–Eveningness (ME) scale, and Subjective Amplitude, measured by the Distinctness (DI) scale. The ME scale assesses individuals’ preferred timing of daily functioning across domains such as mood, attention, and energy, whereas the DI scale evaluates the perceived intensity of diurnal fluctuations in activation; the two scales may be used independently27. In the present study, only the ME scale was used. This scale consists of eight items (e.g., “In the afternoon I work better than in the morning”), including four reverse-scored items. Participants rate their agreement with each statement on a 4-point Likert scale ranging from 1 (no) to 4 (yes). ME scores range from 8 to 32, with higher scores indicating a greater tendency toward eveningness and lower scores indicating morningness. In the current sample, the ME scale demonstrated high internal consistency (Cronbach’s α = 0.82).

Bedtime procrastination

The severity of bedtime procrastination was measured using the Polish version28 of the Bedtime Procrastination Scale12. The Bedtime Procrastination Scale (BPS) is a self-report questionnaire consisting of nine items, including four positively worded and five negatively worded statements, that assess behaviors related to delaying bedtime (e.g., “I go to bed later than I had intended”). Participants rate how frequently each behavior occurs using a 5-point Likert scale ranging from 1 (almost never) to 5 (almost always). A total BPS score is computed by averaging responses across items, yielding scores from 1 to 5, with higher scores indicating a greater tendency toward bedtime procrastination. In the present study, the scale demonstrated good internal consistency (Cronbach’s α = 0.82).

Insomnia

The Polish version29 of the Athens Insomnia Scale30 was used to evaluate insomnia. The Athens Insomnia Scale (AIS) is a self-report psychometric instrument designed to assess sleep difficulties in accordance with ICD-10 criteria. It consists of eight items covering multiple domains of sleep, including sleep induction, awakenings during the night, final awakening, total sleep duration, and overall sleep quality. The scale also assesses daytime consequences of sleep problems, such as well-being, functional capacity, and daytime sleepiness. Respondents rate the severity of each symptom over the past month using a 4-point Likert-type scale ranging from 0 (no problem) to 3 (severe problem). Total scores range from 0 to 24, with a score of 8 identified as the optimal cutoff for insomnia in the Polish population. In the present study, the AIS demonstrated excellent internal consistency (Cronbach’s α = 0.91).

Statistical analysis

Data were analyzed using IBM SPSS Statistics for Windows (version 31.0) and AMOS (version 31.0; IBM Corp., Armonk, NY, USA). First, Harman’s single-factor test was applied to evaluate common method bias, confirming that it remained below the acceptable threshold of 40%. Next, the normality of all measured variables was assessed using one-sample Kolmogorov–Smirnov tests. No significant deviations from normality were observed; therefore, the use of parametric statistics was justified. Pearson correlation analyses were conducted to examine associations among the variables of interest, and relevant tests were performed to assess the potential presence of multicollinearity. Subsequently, structural equation modeling (SEM) was employed to investigate the role of bedtime procrastination in the relationship between chronotype and insomnia, based on theoretical evidence suggesting that bedtime procrastination may mediate the effect of chronotype on insomnia severity, while controlling for age and gender. The mediation model was estimated as an observed-variable path model using maximum likelihood estimation in AMOS. Structural model fit was evaluated based on established thresholds: χ2/df ≤ 5.00, CFI ≥ 0.90, TLI ≥ 0.90, RMSEA ≤ 0.08, and SRMR ≤ 0.08 (Kline, 2023). The significance of indirect effects was evaluated using bias-corrected bootstrapping with 5,000 resamples and a 95% confidence interval (CI). Indirect effects were considered statistically significant if the CI did not include zero.

Results

Potential common method bias was assessed using Harman’s single-factor test. Five factors with eigenvalues greater than 1 were extracted, with the first factor accounting for 27.17% of the total variance, which is below the 40% threshold. These results suggest that common method bias is unlikely to have influenced the study’s findings.

Descriptive statistics for all study variables are presented in Table 1. Although chronotype was analyzed as a continuous variable in the main analyses, a dichotomous categorization was used for descriptive purposes (see Table 1). Table 2 provides item-level mean scores for the Athens Insomnia Scale, illustrating symptom prevalence within the sample. Additionally, 49% of participants scored ≥ 8 on the Athens Insomnia Scale, the threshold commonly used to indicate the presence of insomnia.

A correlation analysis was conducted to examine the associations between chronotype, bedtime procrastination, and insomnia. Table 3 presents the intercorrelations among the study variables. All variables were positively correlated. The strongest association was observed between bedtime procrastination and chronotype (r = 0.49, p < 0.01), followed by a moderate correlation between bedtime procrastination and insomnia (r = 0.30, p < 0.01). The weakest correlation was found between insomnia and chronotype (r = 0.13, p < 0.01). Furthermore, multicollinearity diagnostics demonstrated that multicollinearity was not present, as all tolerance values exceeded 0.91 and all variance inflation factor (VIF) values were below 1.09.

Table 1 Descriptive statistics of the measured variables.
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Table 2 Descriptive statistics for the Athens Insomnia Scale.
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Table 3 Pearson correlations among chronotype, bedtime procrastination, and insomnia.
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The hypothesized structural equation model was tested using AMOS, and the results indicated a good fit to the data, χ²/df = 3.02, CFI = 0.93, TLI = 0.92, SRMR = 0.07, and RMSEA = 0.05, meeting the recommended cutoff criteria31. Bootstrapping methods were used to test the significance of the mediating effect, with chronotype as the independent variable, bedtime procrastination as the mediator, insomnia as the dependent variable, and age and gender as control variables. The results are presented in Table 4; Fig. 1. Chronotype was significantly associated with insomnia (β = 0.23, p < 0.001) and with bedtime procrastination (β = 0.49, p < 0.001). Bedtime procrastination was positively associated with insomnia (β = 0.39, p < 0.001). The direct effect of chronotype on insomnia was significant (β = 0.04, p < 0.001), and the indirect effect of chronotype on insomnia via bedtime procrastination was significant (β = 0.19, 95% CI [0.15; 0.24] ). These findings suggest that bedtime procrastination partially mediated the relationship between chronotype and insomnia.

Fig. 1
Fig. 1The alternative text for this image may have been generated using AI.
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The mediating effect of bedtime procrastination on the relationship between chronotype and insomnia. ***p < 0.001.

Table 4 The mediation effect of bedtime procrastination on the association between chronotype and insomnia.
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Discussion

The present study assessed the relationships between chronotype, bedtime procrastination and insomnia. The findings support a positive association between an evening chronotype and insomnia, consistent with previous cross-sectional7 and longitudinal studies8. However, the small magnitude of the direct effect of chronotype on insomnia suggests that this association may have limited clinical relevance and should therefore be interpreted with caution. Furthermore, the evening chronotype was positively linked to a tendency to delay bedtime, aligning with earlier research on the relationship between eveningness and bedtime procrastination14. Finally, a tendency toward bedtime procrastination was found to be associated with an increase in insomnia symptoms22,24.

The mediation analysis revealed a significant indirect effect of chronotype on insomnia through bedtime procrastination, with the direct effect of chronotype on insomnia also remaining significant, resulting in a significant total effect. This pattern is consistent with partial mediation32, suggesting that the relationship between chronotype and insomnia is partially mediated by bedtime procrastination. These findings underscore bedtime procrastination as a potential mechanism linking eveningness to increased insomnia symptoms and highlight the importance of addressing bedtime-related behaviors to reduce insomnia risk in individuals with evening chronotypes.

To the best of the author’s knowledge, this study is among the first to examine the potential mediating role of bedtime procrastination in the relationship between chronotype and insomnia. Previous research has highlighted the mediating role of bedtime procrastination in the relationships between active emotional regulation strategies and insomnia severity33, chronotype and sleep quality25, repetitive negative thoughts and insomnia symptoms34 and sleep effort and insomnia severity35. The present study expands on these findings by exploring bedtime procrastination’s role in the relationship between insomnia and other sleep-related factors.

Traditional procrastination typically involves delaying a task perceived as aversive—boring, frustrating, or anxiety-provoking. Individuals postpone or avoid such tasks in order to gain short-term positive affect at the expense of long-term goals. Consequently, the ability to adaptively cope with aversive emotional states reduces the likelihood of procrastination36. In contrast, going to bed is unlikely to be considered aversive by most people; in fact, diary studies indicate that sleep receives above-average enjoyment ratings13. Thus, unlike many activities that people unnecessarily postpone, going to bed is generally not viewed as unpleasant. Instead, the aversive component may lie not in initiating sleep but in discontinuing pleasurable or personally meaningful activities. What remains unclear is whether evening chronotypes’ tendency toward bedtime procrastination is due to reduced self-control or is better explained as “revenge bedtime procrastination,” driven by a lack of free time in their daily schedule. This phenomenon offers a potential explanation for why individuals may repeatedly delay their bedtime despite recognizing the negative consequences. Given that evening chronotype has been linked to emotional dysregulation, impulsive behavior, and heightened reward sensitivity37, eveningness may increase the tendency to engage in pleasurable activities (such as using electronic devices) at the cost of initiating sleep. Information from electronic devices (such as games, videos, and social media) is highly stimulating and may delay sleep onset and reduce sleep duration by promoting pre-sleep physiological and psychological arousal38, ultimately contributing to insomnia39.

These considerations suggest that bedtime procrastination may involve both behavioral delays (e.g., later sleep timing) and cognitive–emotional delays (e.g., digital engagement). Thus, further research is needed to clarify the motivational and emotional mechanisms linking chronotype, bedtime procrastination and insomnia.

The current study highlights the potential role of circadian preference in both bedtime procrastination and its consequences, particularly insomnia. This emphasizes the need to consider circadian factors in psychotherapeutic interventions. Since chronotype is already addressed during the psychoeducation phase of cognitive behavioral therapy for insomnia (CBT-I), therapists may benefit from placing greater emphasis on its relevance to bedtime procrastination and associated sleep difficulties. A recent intervention40 aimed at reducing bedtime procrastination showed a significant decrease in insomnia severity, with continued improvement at a one-month follow-up. Similarly, Jeoung et al.41 reported positive results for a behavioral intervention targeting bedtime procrastination, with improvements in the Insomnia Severity Index in a non-clinical sample. These studies provide strong evidence for the effectiveness of such interventions. Integrating chronotype and bedtime procrastination could further enhance their impact on preventing and reducing insomnia.

Limitations and future directions

The primary limitation of this study is the correlational nature of the data. While the author proposed that bedtime procrastination preceded insomnia, all variables were measured simultaneously, which precludes conclusions about temporal precedence or causality. Future research employing a longitudinal design would be more suitable for conducting mediation analyses.

Second, another limitation is that alternative models were not tested. In addition to the proposed mediation model, it would be relevant to examine whether insomnia symptoms might precede bedtime procrastination. Testing alternative models in future research would strengthen the interpretation of the observed associations.

Third, the present sample was disproportionately female. This imbalance may have influenced the results for chronotype and bedtime procrastination, as men tend to be more evening-oriented42 and women report slightly higher levels of bedtime procrastination43. Although gender was statistically controlled in the analyses, future studies should aim to recruit more gender-balanced samples to enhance generalizability.

Fourth, recruitment via social media may have introduced sampling bias, overrepresenting younger and more technologically literate individuals. Consistent with this, the mean age of female (31.89 years) and male participants (28.56 years) in the present study was considerably lower than the corresponding national population averages (44.4 years for women and 41.0 years for men). These factors could limit the generalizability of the findings to older or less tech-engaged populations. Future studies should employ more diverse recruitment strategies to enhance representativeness.

A further limitation is that self-regulation, a theoretically relevant factor linking chronotype and bedtime procrastination, was not measured, limiting insights into the mechanisms underlying bedtime procrastination and insomnia.

A growing body of research links chronotype to diverse behavioral, psychological, and physiological factors not assessed in the present study. Evening chronotypes, for example, report higher alcohol consumption44, increased smoking and BMI45 unhealthy eating patterns, elevated stress hormones46 and more frequent electronic device use after lights out47. An evening chronotype is also associated with greater stress exposure, elevated risk of anxiety and mood disorders, poorer sleep quality, and reduced well-being37. Given that the current study examined only a limited set of variables, future research should incorporate a broader range of behavioral, physiological, and psychosocial measures to better clarify the mechanisms linking circadian rhythms with procrastinatory behaviors and sleep-related outcomes. Additionally, the exclusive reliance on self-report measures may increase the risk of common method bias. Although statistical analyses suggested that common method bias was unlikely to substantially affect the results, future studies could further minimize this risk by adopting multi-method approaches. In particular, incorporating additional subjective measures, such as sleep diaries, alongside objective sleep assessments, such as actigraphy, would allow for a more comprehensive assessment of sleep-related variables.

Finally, considering the central role of insomnia as assessed by the Athens Insomnia Scale, it is important to determine which specific symptoms contribute most substantially to the overall insomnia construct. Future research may employ symptom-level network analyses, such as Gaussian Graphical Models, to investigate the interrelations among individual insomnia symptoms. Such approaches can enhance understanding of the underlying structure of insomnia and facilitate the development of more precise and targeted intervention strategies.

Conclusions

In summary, the present study examined bedtime procrastination as a potential mediator in the relationship between chronotype and insomnia. The findings suggest that (1) chronotype was significantly associated with bedtime procrastination, and (2) bedtime procrastination partially mediated the association between chronotype and insomnia.

To the best of the author’s knowledge, this study is among the first to explore the role of bedtime procrastination in the relationship between chronotype and insomnia. These findings provide insights into possible mechanisms connecting chronotype with insomnia and may have implications for the development of targeted prevention strategies and intervention programs.