Melatonin for Schizophrenia


By Erin Hawkes, MSc

Melatonin is a naturally occurring hormone in the body, produced by a gland in the brain (the pineal gland). It acts directly on sleep, regulating the sleep-wake cycle. An anti-oxidant 6 to 10 times better than vitamin E, melatonin is decreased in schizophrenia, particularly in chronic patients.

Likely Effectiveness: Likely to partially treat medication side effects, such as tardive dyskinesia, and helpful for insomnia, weight gain, and high blood pressure. Effective as an adjunct therapy to antipsychotics, since it does not decrease symptoms of schizophrenia on its own.

Effective Dosage: 0.5mg to 10mg per day as a supplement. It may be administered as capsules, tablets, liquids, or as transdermal patches. Oats, sweet corn, and rice are the best food sources of melatonin (although in significantly lower amounts than are taken in supplements).

Research: Quality experiments: “double-blind, placebo-controlled, crossover;” well reviewed. Some studies are less recent, but still relevant.

Risks:  No side effects reported at therapeutic doses.

Selected references

1) Anderson G, and Maes M. Melatonin: an overlooked factor in schizophrenia and in the inhibition of anti-psychotic side effects. Metab Brain Dis .2012;27: 113-119.

Melatonin has been implicated in the development and maintenance of schizophrenia. Reviewed in this paper, melatonin’s roles include anti-oxidant and anti-inflammatory effects, as well as changes in sleep, circadian rhythms, and side effects of antipsychotics (tardive dyskinesia and metabolic abnormalities). Melatonin levels are decreased in patients with schizophrenia, particularly at night; more than 80% of people with schizophrenia suffer from disturbed sleep. Melatonin also alleviates some side effects of antipsychotics, such as weight gain and increased blood pressure. For these reasons, melatonin is likely to be a positive adjunct therapy for people with schizophrenia.


2) Suresh Kumar PN, Andrade C, Bhakta SG, and Singh NM. Melatonin in schizophrenic outpatients with insomnia: a double-blind, placebo-controlled study. J  Clin Psychiatry.2007; 68:237-241.

Participants in this study were stable on an antipsychotic (Haldol) and had a chief complaint of insomnia. 20 patients received an average of 3.0mg/night melatonin while 20 others received placebos. By the end of the study (15 days), they reported longer, better sleep: fewer awakenings, no “hangover” effect, faster to fall asleep, improved mood, and improved daily functioning. Since insomnia is stressful and stress exacerbates symptoms of schizophrenia, reducing insomnia is clinically important.


3) Shamir E, Barak Y, Shalman I, Laudon M, et al. Melatonin treatment for tardive dyskinesia: a double-blind, placebo-controlled, crossover study. Arch Gen Psychiatry. 2001;58: 1049-1052.

Among people with schizophrenia who have over 20 to 25 years of exposure to certain antipsychotic drugs, almost 70% develop tardive dyskinesia (TD). The present study examined the efficacy of melatonin, in treating TD. The 16-week, well-designed (“double-blind, placebo-controlled, crossover”) trial for 22 patients with schizophrenia, found that 5.0mg of melatonin, twice a day, demonstrated that melatonin decreases TD. TD severity was assessed using standard testing (AIMS: Abnormal Involuntary Movement Scale). The worse the initial symptoms, the better the response to treatment.

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