About six percent of the population suffers from an affective disorder, a major cause of suicide. Other conditions, such as personality disorders, behavior disorders and the abuse of alcohol and drugs may often be so disabling as to be labeled mental illness. The causes of mental illness are not well understood, although it is believed that the functioning of the brain's neurotransmitters is involved. Heredity may be a factor in mental illness as it is in diabetes and cancer. Stress may contribute to the onset of mental illness in a vulnerable person.
Recreational drugs contribute to the onset, but are unlikely to be the single cause.
Family interaction and early childhood training were once dominant theories of causation, however, current research does not support those theories. Since the causes of long-term mental illnesses are not known, there is no effective prevention and thus, no cures at this time. However, there are treatments available which substantially improve the functioning of persons with these disorders. For most people with these illnesses, an expanding range of medications are available. With well-developed programs, some consumers make a good recovery, hold a job and achieve a satisfactory life.