• Disruptive behavior disorders (Oppositional-Defiant Disorder and Conduct Disorder)
• Mood disorders
• Anxiety disorders
• Tics and Tourette's Syndrome
• Learning disabilities

About 40 percent of individuals with AD/HD have Oppositional Defiant Disorder (ODD). Among individuals with AD/HD, Conduct Disorder (CD), also is common, occurring in 25 percent of children, 45 to 50 percent of adolescents, and 20 to 25 percent of adults.

ODD involves a pattern of arguing with multiple adults, losing one's temper, refusing to follow rules, blaming others, deliberately annoying others, and being angry, resentful, spiteful and vindictive. CD often is described as delinquency. Children who have AD/HD and conduct disorder may have lives that are more difficult than those of children with AD/HD alone.

Individuals with AD/HD frequently have difficulty learning in school. Depending on how learning disorders are defined, up to 60 percent of AD/HD children have a co-existing learning disorder.

Some children, in addition to being hyperactive, impulsive and/or inattentive, may seem to always be in a bad mood. They may cry daily, out of the blue, for no reason. They may frequently be irritable with others for no apparent reason. Both sad, depressive moods and persisting elevated or irritable moods (mania) occur with AD/HD more than would be expected by chance.