The pharmacological treatment of mood and anxiety disorders reduced their morbidity and improved mental health for millions of people. Unfortunately, not all subjects benefit from treatments.

The aim of the present review is to summarize available knowledge about antidepressants and anxiolytics’ genetic, demographic, psychosocial and clinical predictors of response, identifying common and specific predictors.

A literature search was conducted using MEDLINE and references of selected articles. The search strategy sought only studies published in English.

Many predictors have been identified. The main genetic finding regards the serotonin transporter gene promoter (SERTPR) polymorphisms which long variant seems to be related to a positive response to therapy in mood disorders and could have a role in anxiety disorders as well. Other genetic predictors as the catechol-O-methyltransferase, the dopamine receptor and the serotonin receptor polymorphisms have been analyzed. Anyway the role of genetic predictors seems nowadays very limited in common clinical practice.

Among other predictors, the main factors common to most disorders are: a comorbid axis II disorder, early onset and a longer duration of illness, which seem related to a worse response to therapy and the presence of a good social support, a good social adjustment and spirituality related to a better outcome. A number of other specific predictors have also been consistently reported.

Possible limitations and suggestions for future researches and clinical practice based on a more integrated vision of human complexity, network of interactions and dynamicity are explained and discussed.