Data came from 29 World Mental Health Surveys conducted in 27 countries, 19 which were nationally representative and several focussed on selected urban or metropolitan area within the country.

Sample sizes of these surveys ranged from 2,357 (Romania) to 12,790 (New Zealand). A total of 145,990 respondents completed part 1 of the

interview and 80,190 completed part 2 of the interview with an average response rate of 69.5%.

Twenty four DSM-IV disorders were used for this analysis:
→ Mood disorder: MDE, bipolar disorder, dysthymia
→ Anxiety disorder: panic disorder, anxiety, social phobia, specific phobia, agoraphobia,

PTSD, OCD, child and adult separation anxiety disorder
→ Impulse-control disorder: IED, conduct disorder, ADHD, ODD, anorexia nervosa, bulimia nervosa, binge eating disorder
→ Substance-use disorder: Alcohol abuse and dependence, drug abuse and dependence, and nicotine dependence