Finasteride-Induced Depression: New Insights Into Possible Pathomechanisms

Finasteride is a drug used to treat male androgenic alopecia by inhibiting the type II isoform of the enzyme 5-alpha-reductase. This enzyme is involved in the metabolism of steroids, including several 5-alpha-reduced steroids that have neurotrophic, neuroprotective, and anxiolytic properties. Reduced 5-alpha-reductase activity has been observed during depressive illness in humans, and finasteride treatment has been linked to an increase in depressive symptoms. In animal studies, inhibition of 5-alpha-reductase leads to behavioral changes with an increase in depressive and anxious behaviors. A recent animal study focused on the effects of finasteride on neuronal plasticity, and found that finasteride treatment decreased adult neurogenesis in the murine hippocampus. Further controlled clinical trials are needed to investigate depressogenic effects of finasteride treatment in humans.