Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurological brain disorder that manifests as a persistent pattern of inattention and/or hyperactivity. ADHD is broken down into three subtypes: predominantly inattentive ADHD, predominantly hyperactive-impulsive ADHD, and combined type ADHD. ADHD begins in childhood, and has only recently been understood, can persist into adulthood as well. While some children outgrow ADHD, about 50% to 60% continue to have symptoms into adulthood.
Children who have ADHD are often easily distracted by sights and sounds in their environment, are unable to concentrate for long periods of time, are restless and impulsive, have a tendency to daydream, and are slow to complete tasks. Adults who have ADHD may have less pronounced symptoms, such as: Inattentiveness, impulsivity or hyperactivity, Impairment in at least two of three areas -- work, life at home and in social interaction with peers, and a history of childhood symptoms. The exact cause of ADHD isn't known, although there are many theories.
ADHD is broadly defined and pervasive, and the symptoms attributed to ADHD likely have a variety of different causes. The initial triggers could include genetic vulnerabilities, viral or bacterial infections, brain injury, or nutritional deficits. There has been a surge in alternative approaches to ADHD, but these have been vigorously disputed.
There is increasing evidence that variants in the gene for the dopamine transmitter are related to the development of ADHD. This makes sense, as according to other recent studies, people with ADHD usually have an abnormally high number of dopamine neurotransmitters which discard the dopamine before the brain can fully make use of it. The stimulant medications used to treat the disorder are all capable of blocking dopamine neurotransmitters.
The finding of another possible cause stemmed from the observation that children of women who smoked during pregnancy are...