A GWAS not based on the GAIN/IMAGE sample was published by Lesch et al. (2008). In their study they analyzed 343 German patients with persistent ADHD (mean age 32.9 years with a range from 18 to 65, 54.5% male, 61.5% combined subtype, 31.2% inattentive subtype, 7.3% hyperactive–impulsive subtype) and 304 controls (mean age 32.7, 51.3% male). Patients were diagnosed using the Structured Clinical Interview of DSM-IV axis 1 disorders (SCID-I; Jacob et al. 2007), supported by ratings from the Wender Utah Rating Scale and an ADHD diagnostic checklist applying DSM-IV criteria categorically and dimensionally (ADHD-DC) (Rosler et al. 2004). Comorbidity along the entire spectrum was analyzed using SCID-I and SCID-II, the latter assessing axis II disorders. Lifetime comorbidity with major depression was 44.7%, with substance use disorders it was 44.1% (of which 32.0% for cannabis use, 40.6% for alcohol use). Of the 304 controls only 54 were screened for psychiatric disorders prior to inclusion. Genotyping was on the Affymetrix GeneChip Human Mapping 500K sets. Importantly, instead of genotyping individual samples, pools were constructed of the 343 cases and 304 controls,
