Many children with ADHD have accompanying disorders, some mild and treatable, others more severe. People with ADHD show an increased rate of substance abuse and are more likely to suffer injuries, particularly as a result of hyperactive or inattentive behavior. A small percentage of adult ADHD cases are accompanied by Tourette syndrome. Among children with ADHD, 33 to 50 percent have oppositional defiant disorder [source: NIMH]. More common among boys than girls, the condition is characterized by an argumentative, difficult, unruly attitude.
Conduct disorder is found in 40 percent of children with ADHD. The National Institute of Mental Health calls it a very serious condition, one that produces potentially dangerous behaviors, in which children may fight, lie, steal or perform other risky or illegal acts [source: NIMH].
Children with ADHD often have trouble in school, a situation made even more difficult for the 20 to 30 percent who have an accompanying learning disorder, such as dyslexia or difficulty with self-expression [source: NIMH]. The stress of dealing with these and other ADHD-related problems can spur the development of anxiety and depression, although proper treatment of ADHD can help to stave off these issues. Some ADHD sufferers also experience bipolar disorder. These conditions often have overlapping symptoms, the manic and depressed states representative of bipolar disorder seem similar to ADHD behavior.
ADHD and its related disorders don't simply disappear as a child passes into adolescence. It's during this time that the problems caused by the disorder can pose the greatest difficulties. For example, teenage drivers with ADHD are much more likely to have auto accidents than those who don't have ADHD [source: NIH].
Many people "outgrow" their ADHD as they enter adulthood. But up to 70 percent of people who have ADHD as children also have it as adults [source: NIMH]. As many as 5 million adults in the U.S. may have undiagnosed ADHD [source: ADDitude]. Some of these undiagnosed cases may suspect something is wrong or may attribute other causes to their issues, which can include difficulty concentrating, multiple car accidents, depression or anxiety.
In diagnosing ADHD in adults, specialists look for signs that the symptoms developed early in childhood and aren't manifestations of other problems. Like children, adults with ADHD often turn to a combination of therapy and medication for treatment, though adults take antidepressants more often than children. Some adults are afraid to confront their condition for fear of how treatment might change them. They may also associate their ADHD with creative or artistic impulses. But numerous testimonials exist of people diagnosed in adulthood with ADHD who received treatment and saw immense improvement in their lives, particularly in their ability to remain organized and complete tasks.
For more information about ADHD and related topics, please check out the links on the next page.