Insomnia is frequent in schizophrenia and associated with night eating and obesity

Sleep difficulties are common in schizophrenia, however these complaints are often overshadowed by more prominent clinical concerns. The point prevalence of insomnia in this population is not well documented. Poor sleep is associated with lower quality of life, impaired cognition, and weight gain.

The objectives of this study are to evaluate the prevalence of insomnia in schizophrenia and to explore the relationship of sleep to cognition, quality of life, and clinical variables.

175 outpatients with schizophrenia or schizoaffective disorder were assessed for insomnia. Participants were evaluated for sleep difficulties, sleep patterns, body mass index, and psychiatric symptoms. Participants were also administered a brief cognitive assessment of processing speed.

44% of the sample currently met the criteria for clinical insomnia. An additional 4% were successfully treated with medications. Insomnia was associated with depression and was an independent predictor of lower quality of life. Insomnia was also associated with high rates of night eating and patients with severe insomnia were significantly more obese. The type of antipsychotic did not account for the difference in body mass index. No difference between group means in cognition was detected, although those with severe insomnia did perform least well.

Clinical insomnia in outpatients with schizophrenia is highly prevalent and has a negative impact on quality of life and psychiatric symptoms. This study offers additional support to the association between poor sleep and higher weight, as well as indicating a potential link to night eating in this population. Assessment for sleep difficulties should be a routine part of clinical care.