There are a variety of presentations of disorders that co-occur (or are “comorbid”) with ADHD, and some are more likely to co-occur in adults, whereas some are more likely to co-occur in children. Mood disorders like anxiety and depression are commonly diagnosed along with ADHD. Sometimes it can be difficult to identify which came first — depression/anxiety or ADHD. Learning disorders like dyslexia, dysgraphia, or dyscalculia are often comorbid with ADHD, as is Autism Spectrum Disorder (ASD). In addition, substance use disorders, Oppositional Defiant Disorder (ODD), and Conduct Disorder are frequently diagnosed alongside ADHD.
There is also evidence to suggest that a high percentage of people with eating disorders also have ADHD. One study conducted by Harvard Medical School found that girls with ADHD were almost four times more likely to have an eating disorder than those without ADHD.