Book excerpt: Abstract: Attention-Deficit/Hyperactivity Disorder, once believed to be a childhood disorder, is now known to persist into adulthood, with 30 to 70% of children diagnosed with ADHD experiencing symptoms of ADHD as adults. Negative outcomes of adult ADHD seen in the literature include: deficits in career or academic performance, interpersonal relations, and increased engagement in risk behaviors such as impulsive spending, smoking, alcohol, and other substance use. The current study used a survey assessment method to examine the effects of ADHD in a sample comprised primarily of first year college undergraduates. Approximately 16% (47) of the 300 students surveyed were included in the ADHD group based on symptoms endorsed on Barkley's Adult ADHD Screening instrument and self-reported diagnosis of ADHD. Results indicate that students who endorse ADHD symptoms perceive themselves as less socially competent than their peers and as having less social support. However, the students reported significantly lower GPA's as compared to their peers as well as significantly lower college adjustment. The students in the ADHD group endorsed significantly greater substance use and associated risk behaviors. Specifically, students in the ADHD group reported greater tobacoo, alcohol, marijuana, methamphetamine, and amphetamine use. Students in the ADHD group reported engaging in a significantly greater number of rish behaviors associated with substance abuse across all areas surveyed excluding sexual risk behaviors. Finally, ADHD symptom endorsement, social behavior, academic performance, substance use and risk behaviors were found to be significant predictors of college adjustment.