The Relationship Between Insomnia and Depressive Symptoms in a Sample of Patients With Schizophrenia: Do Psychotic Symptoms Play a Mediating Role?

Introduction: Depressive symptoms, bidirectionally associated with insomnia, are common comorbidity among patients with schizophrenia. The current literature lacks conclusive evidence about the mediating role of either positive or negative symptoms in the relationship between insomnia and depressive symptoms.

Aim/question: This study aimed to examine the mediating role of psychotic symptoms on the relationship between insomnia and depression in a sample of patients with schizophrenia.

Methods: A cross-sectional, mediational design was used in this cross-sectional study, using a convenience sampling method to recruit 279 patients with schizophrenia.

Results: Insomnia total score ( $\beta$ = 0.351, p < 0.001), work status ( $\beta$ = 3.053, p < 0.001), living arrangement ( $\beta$ = -2.071, p = 0.019), number of previous suicide attempts ( $\beta$ = 1.087, p < 0.001) and medication adherence ( $\beta$ = -1.456, p = 0.031) explained 41.9% of the variability in depression total score (F = 41.14, p < 0.001). Negative psychotic symptoms positively (partially) mediated the relationship between insomnia and depression (p < 0.001).

Discussion: The indirect effect for the negative psychotic symptom total score was significant and positive. This finding implies that, on average, higher insomnia total scores increase negative psychotic symptom total scores, which then increase depression scores.

Implications for practice: The study highlights the significance of early detection and management of insomnia by integrating sleep assessments into standard mental health care to mitigate the negative impact of insomnia on both psychotic and depressive symptoms. Furthermore, this proactive approach may help mental health nurses improve patients' long-term outcomes by addressing these comorbidities before they escalate.