Researchers at the Hebrew University, and Hadassah Medical School in Israel, say the possibility of a connection between jet lag and psychiatric disorders has been underestimated, and suggest it could trigger existing or new cases of affective disorders such as depression, anxiety disorder or panic attacks.

Just how jet lag could trigger new episodes of mental illness is not clear, but, again, the hormone melatonin could be the villain. Because it is a key player in the regulation of the circadian cycle, changes of circadian rhythm and melatonin secretion abnormalities have been linked to a number of mental disorders. The researchers cite studies suggesting that abnormal melatonin metabolism may be directly related to schizophrenia. It's also suggested that sleep deprivation affects melatonin production and may be linked to manic episodes.