Psychologists and psychological associates are trained in the assessment, treatment and prevention of behavioural and mental conditions. They diagnose neuropsychological disorders and dysfunctions as well as psychotic, neurotic and personality disorders and dysfunctions. In addition, psychologists and psychological associates use a variety of approaches directed toward the maintenance and enhancement of physical, intellectual, emotional, social and interpersonal functioning.

Psychologists and psychological associates usually focus their practice in specific areas such as clinical psychology, counselling psychology, clinical neuropsychology; school psychology; correctional/forensic psychology; health psychology; rehabilitation psychology; or industrial/organizational psychology. Within these areas a psychologist or psychological associate may work with a variety of individual client populations such as children, adolescents, adults or seniors, or may focus their attention on families, couples or organizations. They work in a range of settings including schools, hospitals, industry, social service agencies, rehabilitation facilities and correctional facilities. Many psychologists and psychological associates have their own private practice.