There are growing amounts of data available on the impact of finasteride on sexual and mood disorders. This coexistence of adverse events should be considered rather as a distinct syndrome with its own pathogenesis than a random co-occurrence of signs. Post-marketing follow-ups suggested the possibility of persistent symptoms after drug discontinuation, which is referred to as PFS. Despite the lack of final proof, the presence of severe and persistent side effects caused by the treatment of an aesthetic problem raises great concern for the clinician. A low estimated prevalence of PFS cannot be an excuse for nonvigilance since the drug is used by millions of relatively young and healthy individuals. The potential risk of adverse effects, including the length of treatment, should be carefully discussed with each patient before the onset of treatment.
—Post-finasteride syndrome: Does it really exist? The Aging Male, January 16, 2019