Calcitonin and bipolar disorder: a hypothesis revisited.

Double-blind trials conducted in the early 1980s showed that subcutaneous injections of salmon calcitonin in patients suffering from mania resulted in significant decreases in irritability, euphoria and hyperactivity. Although these results were promising, there were no follow-up studies in this area. A MEDLINE search into the effect of calcitonin on neuronal tissues revealed that calcitonin affects neuronal tissues in a manner similar to that of the currently accepted mood-stabilizing agents--namely by modulating intracellular second messenger signalling mechanisms, stabilizing neuronal membranes and inhibiting neuronal calcium influx. We suggest that these effects of calcitonin on neuronal tissues, combined with earlier clinical research showing its efficacy in treating the acute symptoms of mania, make calcitonin a candidate for further research in the treatment of bipolar disorder.