Sexual dysfunctions as side effects of antidepressant treatments are being reported more and more frequently: they are one of the main reasons of dropout from therapy. These side effects are reported in between 20% and 40% of cases. The aim of this study is to highlight, following the actual evidence from the field of psychopharmacology, how these side effects may not be directly related to the antidepressant treatment; on the contrary we show that, following the observational clinical data obtained in our Mental Health Dept., a careful clinical interview about the sexual behaviour of the patients allows psychotherapy to interact with pharmacotherapy, in order to reduce the drug dosage, or replace it with another drug, and/or to combine an erectile dysfunction treatment with the psychopharmacological therapy. This careful clinical interview about the sexual behavior of the patients will more clearly determine the percentages of sexual dysfunction side effects, and also avoid drop-out from antidepressant therapy.