Edmonton: There is no evidence that melatonin is effective in treating secondary sleep disorders or preventing jet lag, finds a study published online by the British Medical Journal.

Sleep disorders are a widespread problem and place a burden on society through their negative impact on quality of life, safety, productivity, and healthcare utilisation.

Complementary and alternative therapies, such as melatonin (a hormone that is thought to play a part in controlling daily body rhythms) have been used increasingly to manage sleep disorders.

Researchers at the University of Alberta, Canada analysed trials of the effects of melatonin on people with secondary sleep disorders (sleep problems associated with medical, neurological or substance misuse) and sleep disorders arising from sleep restriction, such as jet lag or shiftwork disorder.

They found no evidence that melatonin is effective in treating secondary sleep disorders or sleep disturbance in people with jet lag or people with shiftwork disorder, say the authors. There is evidence that melatonin is safe with short term use, but further studies are needed to determine its long term safety, they conclude.