Psychology concerns the study of the mind and behaviour that differentiates into cognitive, forensic, social, and developmental psychology. Psychologists work with individuals, couples, and families to help them make desired changes to behaviours. They identify, assess, diagnose and treat mental, emotional and behavioural disorders. Clinical psychologists assist people to face a variety of problems ranging from short-term personal issues to severe, chronic conditions. A child psychologist may provide assessment of special learning needs or custody issues. Within court, psychologists can provide assessments for the criminal justice system, or evaluate and provide professional psychological opinion. Importantly, psychologists cannot prescribe medications.