In this article the mental disease is studied a three different levels: the exclusion of
criminal capacity; in order to exercise the defence inside criminal process; in the execution of imprisonment. In each of these levels criminal justice reserves to the subject affected of a mental
disorder a differentiated treatment. The aim of the study is to verify whether the rules on mental
illness in these three phases, at the moment of the crime, during the criminal process and during
the execution of the punishment, respects the rights constitutionally protected.