D. Sample 4) Taiwanese methamphetamine-dependent vs control: Unrelated subjects recruited in Taipei included 140 methamphetamine-dependent individuals diagnosed independently by each of two psychiatrists using DSM IV criteria [103–108] and 240 matched Han Chinese controls who denied any history of use of illegal drugs and denied any histories of psychotic symptoms. Subjects were 30% female and averaged 32.5 +/− 10 years of age. Dependent individuals reported methamphetamine use > 20 times/year, or described well-documented methamphetamine psychosis with lower levels of regular use. They denied histories of psychosis either prior to methamphetamine use or in relation to other psychedelic drugs. Most reported use of at least one other addictive substance. Controls denied illegal drug use or psychotic symptoms and were matched for gender and age.
