Objectives Sleep disturbances and circadian rhythm disruption are highly prevalent in major depressive disorder (MDD) and may contribute to poorer functioning and reduced treatment adherence. However, few studies have examined sleep quality, biological rhythm disruption, functioning, and medication adherence concurrently in an outpatient depression sample. This study investigated the relationships among sleep quality, biological rhythm, functional status, medication adherence, and depression severity in patients diagnosed with depression. Methods A descriptive, correlational cross-sectional study was conducted in the Adult Psychiatry Outpatient Clinic of Maltepe University Faculty of Medicine Hospital between 16 December 2024 and 15 March 2025. A total of 110 patients with a confirmed diagnosis of depression were included. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), biological rhythm disruption using the Biological Rhythm Interview of Assessment in Neuropsychiatry (BRIAN), functional status using the Social Functioning Scale (SFS-T), medication adherence using the Medication Adherence Rating Scale (MARS), and depression severity using the Beck Depression Inventory (BDI). Pearson correlation analyses were used to examine associations among variables, and multiple linear regression analyses were conducted to identify independent factors associated with sleep quality. Results Sleep impairment was common: 46.4% of participants reported moderate sleep quality and 31.8% reported poor sleep quality. Mean PSQI score was 8.31 (SD = 4.21). Poorer sleep quality (higher PSQI scores) was moderately associated with lower social functioning (r = − 0.300, p < 0.01) and lower medication adherence (r = − 0.350, p < 0.01), and strongly associated with greater biological rhythm disruption (r = 0.621, p < 0.01). Sleep quality was also positively correlated with depression severity (r = 0.494, p < 0.01). Sleep impairment was common: 46.4% of participants reported moderate sleep quality and 31.8% reported poor sleep quality. Poorer sleep quality (higher PSQI scores) was moderately associated with lower social functioning (r = − 0.300, p < 0.01) and lower medication adherence (r = − 0.350, p < 0.01), and positively associated with biological rhythm disruption (r = 0.621, p < 0.01) and depressive symptom severity (r = 0.494, p < 0.01). In the multiple linear regression analysis, the overall model was statistically significant (R² = 0.429, p < 0.001), explaining 42.9% of the variance in sleep quality. After adjustment for the other variables, biological rhythm disruption remained the only independent predictor of sleep quality (β = 0.445, p < 0.001). Conclusions In this outpatient depression sample, poor sleep quality was significantly associated with circadian rhythm disruption, reduced functioning, lower medication adherence, and greater depressive symptom severity. These findings support the clinical value of early sleep screening and integrated approaches that address sleep–circadian regulation alongside functional recovery, with possible benefits for treatment engagement in outpatient mental health care. Clinical trial number Not applicable.

Sleep quality, circadian rhythm disruption, functioning, and treatment adherence in major depression: a cross-sectional exploratory study

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2026年7月31日

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İrem Gedikli,
Ece Alagöz

摘要

Objectives

Sleep disturbances and circadian rhythm disruption are highly prevalent in major depressive disorder (MDD) and may contribute to poorer functioning and reduced treatment adherence. However, few studies have examined sleep quality, biological rhythm disruption, functioning, and medication adherence concurrently in an outpatient depression sample. This study investigated the relationships among sleep quality, biological rhythm, functional status, medication adherence, and depression severity in patients diagnosed with depression.

Methods

A descriptive, correlational cross-sectional study was conducted in the Adult Psychiatry Outpatient Clinic of Maltepe University Faculty of Medicine Hospital between 16 December 2024 and 15 March 2025. A total of 110 patients with a confirmed diagnosis of depression were included. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), biological rhythm disruption using the Biological Rhythm Interview of Assessment in Neuropsychiatry (BRIAN), functional status using the Social Functioning Scale (SFS-T), medication adherence using the Medication Adherence Rating Scale (MARS), and depression severity using the Beck Depression Inventory (BDI). Pearson correlation analyses were used to examine associations among variables, and multiple linear regression analyses were conducted to identify independent factors associated with sleep quality.

Results

Sleep impairment was common: 46.4% of participants reported moderate sleep quality and 31.8% reported poor sleep quality. Mean PSQI score was 8.31 (SD = 4.21). Poorer sleep quality (higher PSQI scores) was moderately associated with lower social functioning (r = − 0.300, p < 0.01) and lower medication adherence (r = − 0.350, p < 0.01), and strongly associated with greater biological rhythm disruption (r = 0.621, p < 0.01). Sleep quality was also positively correlated with depression severity (r = 0.494, p < 0.01). Sleep impairment was common: 46.4% of participants reported moderate sleep quality and 31.8% reported poor sleep quality. Poorer sleep quality (higher PSQI scores) was moderately associated with lower social functioning (r = − 0.300, p < 0.01) and lower medication adherence (r = − 0.350, p < 0.01), and positively associated with biological rhythm disruption (r = 0.621, p < 0.01) and depressive symptom severity (r = 0.494, p < 0.01). In the multiple linear regression analysis, the overall model was statistically significant (R² = 0.429, p < 0.001), explaining 42.9% of the variance in sleep quality. After adjustment for the other variables, biological rhythm disruption remained the only independent predictor of sleep quality (β = 0.445, p < 0.001).

Conclusions

In this outpatient depression sample, poor sleep quality was significantly associated with circadian rhythm disruption, reduced functioning, lower medication adherence, and greater depressive symptom severity. These findings support the clinical value of early sleep screening and integrated approaches that address sleep–circadian regulation alongside functional recovery, with possible benefits for treatment engagement in outpatient mental health care.

Clinical trial number

Not applicable.