DSM-5 (Research Starter)Mental illnesses are purportedly the result of abnormalities in brain structure and functioning. People are predisposed to symptoms of mental illnesses by unknown combinations of genetic predispositions (nature) and environmental and life experiences (nurture) that trigger inherited or acquired vulnerabilities to express symptoms (self-reported distress) and signs (observable indicators) of these diseases. As reflected in the DSM-5, psychiatric disorders can afflict children and the elderly, men and women, and people of all races, ethnicities, and nationalities.