Table 1.

Features of studies included in the systematic review

Study	Characteristics of participants	Intervention (active group)	Intervention (control group)	Duration of FU (wk)	Study outcome
Borba et al., 201120)	19 patients, 18–65 yr, either schizophrenia or schizoaffective disorder	Olanzapine, clozapine, quetiapine or risperidone, ramelteon 8 mg/day	Olanzapine, clozapine, quetiapine or risperidone, placebo	8	Decrease in total cholesterol level and a reduction in fat in the abdominal and trunk areas in ramelteon group
Modabbernia et al., 201413)	34 males and females adults, 18–65 yr, first episode schizophrenia	Olanzapine 25 mg/day and clonazepam 2 mg melatonin 3 mg	Olanzapine 25 mg/day and clonazepam 2 mg placebo	8	Less weight gain, BMI, waist circumference & triglyceride level in melatonin group
Mostafavi et al., 201421)	48 adolescents, 11–17 yr, first time diagnosis of bipolar mood disorder	Melatonin (3 mg/day), lithium carbonate (3–4 mg/day) and olanzapine (5–10 mg/day)	Placebo, lithium carbonate (3–4 mg/day) and olanzapine (5–10 mg/day)	12	Melatonin attenuates increase of systolic BP and cholesterol level
Romo-Nava et al., 201422)	44 adults, 18–45 yr, schizophrenia or bipolar disorder type I	Olanzapine, clozapine, risperidone, or quetiapine 5-mg slow-release melatonin	Olanzapine, clozapine, risperidone, or quetiapine, placebo	8	Melatonin attenuates the increase of diastolic BP, fat mass, and triglyceride level In the bipolar disorder group
Mostafavi et al., 201723)	38 (19 patients per arm) bipolar I disorder patients; within the age of 11–17 yr	Olanzapine, lithium carbonate and melatonin 3 mg/day	Olanzapine, lithium carbonate and placebo	12	Melatonin attenuates the sharp weight gain side effect of these drugs to near significance

FU, follow-up; BMI, body mass index; BP, blood pressure.