Objectives
Leptin is an important factor involved in the regulation of feeding behavior, and its discovery has opened new perspectives in the study of obesity. Given that patients with a diagnosis of affective disorders frequently show appetite loss, weight decrease and dysfunctions of the hypothalamic-pituitary-adrenal axis, and that leptin seems to induce anorexia by interacting with specific neuroendocrine and neurotransmission systems involved in mood regulation, a possible relationship between leptin serum levels and mood disorders can be hypothesized. The aim of this article is to provide the reader with a comprehensive review addressing this issue.
Methods
A systematic review of the literature on the relationships between leptin, ghrelin and mood disorders has been carried by searching PubMed for all studies on this topic in the period 1995-2010.
Results
Interestingly, it was found that still very few studies have directly investigated leptin plasma levels in affective disorders. Significant reduction of leptin plasma levels in depressed patients has been occasionally reported, however other studies have not confirmed this finding (Table I).
Conclusions
Although the hypothesis of a crucial role of leptin levels on the occurrence, recurrence and specific characteristics features of mood disorders deserves great attention, it should be corroborated by further specific research, since available data still appear sparse and inconsistent.