Sleep is a fundamental physiological process essential for maintaining emotional regulation, cognitive performance, and overall well-being. Disturbances in sleep are increasingly recognized as both symptoms and predictors of psychiatric disorders, most notably depression [1,2]. Globally, nearly three-quarters of individuals with depression report at least one form of sleep disturbance, including insomnia, difficulty maintaining sleep, early morning awakening, hypersomnia, or nightmares [3]. Such disturbances not only exacerbate depressive symptoms but also contribute to poor treatment response, chronicity, and higher relapse risk [1–3]. Depression itself is a leading cause of disability worldwide and imposes a considerable burden on health systems and societies. In India, its prevalence is estimated between 5% and 7%, with an increasing recognition of coexisting sleep complaints in both psychiatric and primary care settings [4,5]. The bidirectional relationship between depression and sleep disturbances underscores a complex neurobiological interplay, involving circadian rhythm dysregulation, monoaminergic imbalance, and heightened hypothalamic–pituitary–adrenal axis activity [6]. Although studies from Western populations have extensively documented the association between sleep quality and depression severity, there remains a paucity of data from Indian cohorts. Cultural, social, and lifestyle determinants unique to the Indian context may influence both the perception and reporting of sleep disturbances. Identifying specific patterns of sleep disruption in relation to depression severity is therefore critical, as it may provide clinically valuable insights for early diagnosis and the development of tailored therapeutic strategies.Against this backdrop, the present observational study was undertaken to evaluate the prevalence and patterns of sleep disturbances among adults and to examine their association with depression severity.

Study Design and Setting: This was a cross-sectional observational study conducted in the Department of Psychiatry, KIMS & RF General Hospital, Amalapuram, Andhra Pradesh, India. The study was carried out from September 2020 to February 2021. Study Population: A total of 100 adult participants aged between 18 and 60 years were recruited from the outpatient and inpatient psychiatry services. Individuals with a prior diagnosis of depression, new depressive symptoms, or those presenting with sleep-related complaints were considered eligible. Participants with severe neurological disorders, psychotic illnesses, substance dependence (except nicotine), or those unwilling to provide informed consent were excluded. Ethical Considerations: The study was initiated after obtaining approval from the Institutional Ethics Committee of KIMS & RF, Amalapuram. Written informed consent was obtained from all participants prior to inclusion. Data Collection Tools: Sociodemographic Proforma: Collected details on age, sex, marital status, education, occupation, and residence. Patient Health Questionnaire-9 (PHQ-9): Used to assess depression severity, categorized as mild, moderate, moderately severe, or severe. Pittsburgh Sleep Quality Index (PSQI): Applied to evaluate overall sleep quality, with scores >5 classified as poor sleep quality. Sleep Disturbance Checklist: Documented specific disturbances such as insomnia, difficulty maintaining sleep, early morning awakening, hypersomnia, and nightmares. Statistical Analysis: Data were entered into Microsoft Excel and analyzed using SPSS version 26.0. Continuous variables were expressed as mean ± standard deviation (SD), while categorical variables were summarized as frequencies and percentages. Associations between depression severity and sleep disturbances were tested using the chi-square test. Pearson’s correlation coefficient was used to determine the relationship between PHQ-9 and PSQI scores. A p-value < 0.05 was considered statistically significant.

A total of 100 adults participated in the study. The mean age was 36.2 ± 10.8 years, with a slight female predominance (54%) (Table 1). Table 1. Baseline Characteristics of Study Participants (n = 100) Variable Value Sample size 100 Mean age (years) 36.2 ± 10.8 Gender: Male 46% Gender: Female 54% Depression Severity Based on PHQ-9 scoring, 40% of participants had mild depression, 32% moderate, 18% moderately severe, and 10% severe depression (Table 2). Table 2. Distribution of Depression Severity (PHQ-9) Depression Severity Frequency (n) Percentage (%) Mild 40 40 Moderate 32 32 Moderately Severe 18 18 Severe 10 10 Patterns of Sleep Disturbances Insomnia was the most frequently reported disturbance, affecting 48% of participants, followed by difficulty maintaining sleep (42%) and early morning awakening (30%). Hypersomnia and nightmares were less common, reported by 22% and 18% respectively. Notably, 68% of participants had poor overall sleep quality (PSQI > 5), indicating clinically significant sleep disturbance (Table 3). Table 3. Patterns of Sleep Disturbances Sleep Disturbance Frequency (n) Percentage (%) Insomnia 48 48 Difficulty maintaining sleep 42 42 Early morning awakening 30 30 Hypersomnia 22 22 Nightmares 18 18 Poor sleep quality (PSQI > 5) 68 68 Association Between Sleep Disturbances and Depression Severity The prevalence of insomnia showed a strong positive association with depression severity, affecting 90% of individuals with severe depression compared to only 28% in the mild group. Similarly, early morning awakening and nightmares were significantly higher among those with moderately severe to severe depression. Hypersomnia was more common in moderate depression (35%) compared to other groups. These associations were statistically significant, with p-values ranging from <0.001 to 0.04 (Table 4). Table 4. Association Between Sleep Disturbances and Depression Severity Sleep Disturbance Mild (%) Moderate (%) Moderately Severe (%) Severe (%) p-value Insomnia 28 45 72 90 <0.001 Early morning awakening 10 20 38 60 0.01 Nightmares 8 12 28 45 0.01 Hypersomnia 12 35 18 10 0.04

This study underscores a robust relationship between sleep disturbances and depression severity among adults attending psychiatric services at KIMS & RF, Amalapuram. Nearly two-thirds of participants reported poor sleep quality, with insomnia emerging as the most frequent complaint. The findings are in line with previous validations of the Pittsburgh Sleep Quality Index (PSQI) in Indian populations, which demonstrated its reliability in detecting poor sleep quality in different cohorts [7]. In our study, sleep maintenance problems and early morning awakening were also common, reflecting the classical circadian rhythm disturbances observed in depressive disorders. A gradient effect between depression severity and sleep disturbances was evident. While only 28% of participants with mild depression reported insomnia, the prevalence rose sharply to 90% in those with severe depression. Nightmares and early morning awakening also increased significantly with severity. These results are consistent with broader literature suggesting that poor sleep is predictive of poor mental health outcomes and contributes to the chronicity of depression [8,9]. Interestingly, hypersomnia was more prominent in moderate depression compared to severe cases. This aligns with evidence that hypersomnia is particularly associated with atypical depression and younger age groups, pointing to heterogeneity in sleep phenotypes across depressive subtypes [10]. The significant positive correlation between PSQI and PHQ-9 scores in this study provides further support for the strong interconnection between poor sleep quality and depressive symptomatology, a pattern also observed in healthcare workers and pandemic-related studies [10]. From a clinical perspective, these findings highlight the need for routine screening of sleep problems in patients with depression. Addressing sleep disturbances through interventions such as cognitive-behavioral therapy for insomnia, sleep hygiene practices, and targeted pharmacotherapy may not only improve sleep quality but also enhance treatment outcomes and reduce relapse [11,12]. Strengths and Limitations: This study employed validated tools (PHQ-9 and PSQI) that have demonstrated reliability in Indian populations [7–9]. However, its cross-sectional design precludes causal inference, and the sample size, though adequate, limits generalizability. The lack of objective assessments such as actigraphy or polysomnography is another limitation. Implications: Our results reinforce the bidirectional relationship between depression and sleep disturbances. Future longitudinal and interventional studies are warranted to establish causal pathways and determine whether improving sleep quality can effectively reduce the severity and recurrence of depression .

The present study demonstrates that sleep disturbances are highly prevalent among adults with depression and show a strong positive association with the severity of depressive symptoms. Insomnia, early morning awakening, and nightmares were particularly frequent in those with moderately severe and severe depression, while hypersomnia was more common in moderate cases. The significant correlation between PSQI and PHQ-9 scores highlights the close interplay between poor sleep quality and depressive symptomatology. These findings emphasize the importance of routinely assessing sleep patterns in individuals with depression. Early identification and management of sleep problems may substantially enhance treatment outcomes, quality of life, and relapse prevention.

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