Attention-Deficit/Hyperactivity Disorder (ADHD), once thought to occur only in children, is now recognized to be a continuing challenge into adulthood for many people; it is best understood as a chronic condition with symptoms experienced over a lifetime. It is estimated to affect as many as 4% of adults worldwide. In the U.S., fewer than 50% of adults who meet the criteria for ADHD have ever been diagnosed and treated for it.
ADHD is characterized by difficulty initiating or completing tasks, sustaining attention, and controlling impulsive actions. Patients may have difficulties with organization and time management. It should not be surprising that difficulties in these functional domains can have serious negative impacts on the educational, social, and occupational lives of those who experience these symptoms.
Three types of ADHD are diagnosed:
- Combined inattentive and hyperactive-impulsive (this is the most common type, found in about 80% percent of patients).
- Predominantly inattentive (about 15%).
- Predominantly hyperactive-impulsive (about 5%)
The terminology can be confusing. Attention Deficit Disorder (ADD) is an older term for what is now called Attention-Deficit/Hyperactivity Disorder (ADHD). There is no longer any disorder “officially” called ADD, but some people still use ADD to refer to the type of ADHD that is predominantly inattentive, and use ADHD for the type of ADHD that is predominantly hyperactive and/or impulsive. However, these all refer to the same disorder, and in regard to medications, the treatments are generally the same. Hyperactive symptoms often improve in adulthood, and it is for this reason that it was previously thought that patients outgrow ADHD. It is now clear, however, that inattentive symptoms usually do not resolve, though they are not always outwardly apparent if someone has structured their life in a way that avoids situations requiring extended periods of sustained focus.
“Adult ADHD” simply refers to patients who have had symptoms of ADHD since childhood and are now adults, whether or not the symptoms were properly recognized and diagnosed during childhood. If no significant symptoms of ADHD were present during childhood and attentional challenges began only in adulthood, the diagnosis is usually something other than ADHD.
Although the precise physiologic cause of ADHD is unknown, a number of associated neurochemical abnormalities have been observed, and considerable evidence suggests that the disorder has both a strong genetic component and a biological underpinning. This pathophysiology includes dysfunction in both norepinephrine and dopamine activity, particularly in the prefrontal cortex.
A recent journalistic (non-scientific, but informative) overview on ADHD.
CQ Researcher Article: Treating ADHD (PDF)