Phosphodiesterase genes and antidepressant treatment response: a review.

Depression results in a tremendous burden to individuals suffering from the disorder and to the global health economy. Available pharmacologic treatments for depression target monoamine levels and monoamine receptors. However, delayed onset of effect, partial or inadequate treatment response, and side-effects are significant limitations of current therapies. The search for a better understanding of mechanisms of depression and for new treatment targets has turned attention to intracellular mediators. Phosphodiesterases (PDEs) are enzymes that break down the intracellular second messenger mononucleotides cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Recent data from animal and human studies indicate that PDEs may play a role in depression and in related stress conditions. PDE genes have been linked directly to depression and to other genes associated with psychiatric disorders.