Up to 80% of patients diagnosed with schizophrenia have a concurrent insomnia disorder. New research shows that cognitive behavioral therapy significantly reduces insomnia in patients with schizophrenia.

In this nonrandomized, assessor blind study, Dong-Ki Hwang from the Department of Psychiatry, Seoul Metropolitan Eunpyeong Hospital, South Korea, and colleagues evaluated the effects of cognitive behavioral therapy for insomnia (CBT-I) in 63 patients with schizophrenia recruited from residential or rehabilitative facilities in Seoul, South Korea.

Patients received either 4 sessions of CBT-I in group sessions plus usual care (n=31) or usual care alone (n=32). The investigators administered the Insomnia Severity Index, Pittsburgh Sleep Quality Index, Psychotic Symptoms Rating Scale, Anxiety Sensitivity Index, and Beck Depression Inventory at baseline, week 4, and week 8.

Compared with the control group, those who received CBT-I demonstrated significant improvement in Insomnia Severity Index scores at both weeks 4 and 8 (medium effect size, d = 0.5 at both points), with a reduction of 6.3 points at week 8 in the CBT-I group. Pittsburgh Sleep Quality Index total score also demonstrated significant improvement at both weeks 4 and 8 (small effect size at week 4, d = 0.4; medium effect size at week 8, d = 0.5). Differences in scores between the 2 groups for the other 3 tools at weeks 4 and 8 were nonsignificant.