Comparing how co-morbid depression affects individual domains of functioning and life satisfaction in schizophrenia

Depression in schizophrenia is often associated with reduced life satisfaction. Yet, it is not clear how depression influences different functioning domains. The relative impact across objective and subjective quality of life (QOL) has also not been clearly compared. This study sought to examine the differences in individual QOL indicators between schizophrenia patients with and without co-morbid depression. This was completed separately for objective and subjective QOL.

57 patients with schizophrenia/schizoaffective disorder were classified into groups with (DP: N=31, M=45.81, SD=10.29) and without depression (NDP: N=26, M=40.54, SD=11.00) using MADRS scores. Objective and subjective QOL was assessed using Lehman's (1988) QOL Interview using five domains: daily activities and functioning, family relations, social relations, safety and health. z-scores were created for these domains (objective and subjective) based on responses from 44 healthy controls (M=39.80, SD=13.94).

Objectively, DP patients had significantly reduced social interaction frequency compared to HCs. Subjectively, DP patients had significantly poorer scores than HCs on all five domains, and additionally reported poorer satisfaction with daily activities and health compared with the NDP group.

Presence of depression in schizophrenia results in reduced self-reported life satisfaction across a broad spectrum of QOL domains. Objectively, depression resulted in decreased interactions with friends and peers, i.e. greater social isolation. The findings support the need to continue developing and implementing peer support groups in schizophrenia, a challenging task especially in the face of depression. More broadly, the assessment of depression in other illnesses is recommended.