Comorbidity of Asperger syndrome: a preliminary report.

Wilkinson et al. (1998) tracked 35 people who had Asperger syndrome. They watched who developed extra mental-health problems during the next two years. A doctor gave each person a full psychiatric exam. The team counted how many met criteria for a second diagnosis.

Two-thirds of the group qualified for at least one more disorder. Kids mostly picked up ADHD. Teens and adults mostly picked up depression. The paper warns that comorbidity is the rule, not the exception.

Lugnegård et al. (2011) later asked the same question in adults and got an even higher mood-and-anxiety tally, so the risk does not fade with age. Mattila et al. (2010) repeated the count in a larger youth sample and again landed near 70%, showing the pattern holds across clinics and communities. Salazar et al. (2015) pushed the age window downward and saw 90% of preschool autistic children already carrying extra diagnoses; the numbers look different but the methods changed, so the studies actually agree that comorbidity starts early and stays common.

If you serve anyone with Asperger syndrome, plan on screening for ADHD, anxiety, and depression every six months. Use parent, teacher, and self-forms because Hurtig et al. (2009) show parents alone miss internalizing signs. Early detection lets you add CBT, social-skills groups, or medication before problem behaviors escalate.