Co-morbidity between cancer and psychiatric disorders including adjustment disorder, depressive disorders or angst can seriously influence the prognosis and the quality of life of patients.

The identification of the psychological and biological profile of patients at risk for such co-morbidity is not yet available. Classical candidate genes such as the BDNF, the 5-HTLPR and genes whose products are involved in inflammatory events have received some attention, but results are inconclusive.

In the present review the association between cancer and psychiatric disorders is reviewed, a focus on the investigation of the Gene X environment and the epigenetic control over the activation of the HPA axis is proposed as a tool to refine the definition of the biologic profile at risk for co-morbidity between psychiatry and cancer.

A number of genes and socio-demographic variables that may influence risk to suffer from a psychiatric disorder after a diagnosis of cancer is identified and discussed. The identification of such biologic and socio-demographic profile is instrumental in the identification of subjects at risk of a double diagnosis, both somatic and psychiatric. An early identification of such profile risk would pave the way to the implementation of early intervention strategies.