The sleep and circadian rhythm disruptions in schizophrenia are attributed to a decrease in nocturnal melatonin level which may worsen if treated with conventional sedative drugs. This study was planned to evaluate the effects of add-on ramelteon on sleep and circadian rhythm disturbances in schizophrenia. A randomized, rater-blinded clinical trial was conducted on 120 patients with schizophrenia. Patients were categorized into predominantly positive (PG) or negative (NG) symptoms depending on Positive and Negative Syndrome Scale (PANSS) scoring, and then they were randomized into control (haloperidol/risperidone) or test (add-on ramelteon) groups. After recruitment, baseline serum melatonin, serum AANAT, urinary melatonin and Pittsburgh Sleep Quality Index (PSQI) were evaluated. Patients were reassessed after 4 weeks of therapy with antipsychotics with or without ramelteon. A significantly greater increase in night-time melatonin level (PG: 10·19; 95%CI: 1·42 to 18·97; p = 0·024; NG: 18·74; 95%CI: 8·48 to 29·0; p = 0·001), decrease in PSQI scores (PG: -1·57; 95%CI: -2·59 to -0·55; p = 0·003; NG: -2·49; 95%CI: -4·59 to -0·39; p = 0·021), increase in urinary melatonin (PG: 0·20; 95% CI: 0·056 to 0·35; p = 0·008; NG :0·15; 95% CI: 0·01 to 0·29; p = 0·034), increase in serum AANAT (PG: 4·61; 95%CI: 1·34 to 7·87; p = 0·007; NG:3·46; 95%CI: 1·30 to 5·63; p = 0·002) and improvement in PANSS score were found in patients receiving add-on ramelteon. The increase in serum melatonin and decrease in PSQI score were greater with predominantly negative symptom group in comparison to positive symptom group. Ramelteon may be considered as an add-on therapy with antipsychotic drugs for sleep and circadian rhythm disturbances in schizophrenia.
