Casi difficili e accertamenti peritali in tema di vizio di mente

Compared to the large number of cases in which the insanity defense is raised, criminal Courts find the defendant insane only in a very small part. Mental illness is often marked as the main cause of violent crimes, but psychologists, criminologists and the case law show that also strong emotions like rage, hate and jealousy could lead a person to act violently. Recent neurosciences studies have highlighted that behaviour has a biological basis, although this does not mean that behaviour is "biologically determined". Many neuroscience researchers have cautioned about a wide array of methodological difficulties and interpretative chiallenges in researching cognitive and brain mechanisms as well as mental disease. Explanations offered by psychological and psychiatric expert witnesses during the criminal proceeding are essential in order to help resolve a range of issues, namely the one of whether the defendant appreciated the wrongfulness of his or her conduct. As the case law discussed in this essay emphasizes, even serious mental illnesses like schizophrenia are not the determining factor of a defendant's inability to control himself. Neuroscience evidence - particularly neuroimage-based evidence - should always be supported by an expert explanation and followed by an independent judicial assessment on the criminal conduct. Finding a defendant not guilty by reason of insanity is a legal conclusion, not a scientific result.