Relationship Between Insomnia and Continued Outpatient Treatment in Psychiatric Patients

Sleep plays an essential role in maintaining both physical and mental well-being. Many patients in psychiatric outpatient settings complain of insomnia. However, the causal relationship between insomnia and depressive symptoms in all mental illnesses remains unclear. Moreover, research on insomnia and the continuation of outpatient treatment is lacking. We hypothesize a high correlation between depression and insomnia among patients with diverse mental illnesses. Additionally, we posit that insomnia significantly influences the continuity of outpatient visits. To this end, we evaluated insomnia and depression symptoms in psychiatric patients both at their initial visit and one year later. We also examined factors related to insomnia at the outset and factors associated with the ongoing utilization of outpatient treatment.

The participants of the study consisted of patients who made their first visit to the outpatient department of psychiatry and neurology at Showa University East Hospital between June 1, 2021, and March 31, 2023, and who continued attending the outpatient clinic for one year. Clinical characteristics were assessed using the Self-rating Depression Scale (SDS) and the Athens Insomnia Scale (AIS).

The study's findings were collected from a cohort of 1106 patients and revealed that more than 70% experienced insomnia at the time of their initial visit. In total 137 patients continued to receive outpatient treatment for one year, and their AIS scores improved from 9 points to 5 points. A multivariate analysis revealed that the SDS items of depressed mood and insomnia were confounding factors influencing AIS improvement.

Given that 70% of patients complained of insomnia at the time of their first visit and that sleep improved in many of the 12.4% of patients who continued to receive outpatient treatment for at least one year, the results suggest that sleep status is an important determinant of whether a patient continues to attend outpatient clinics.