Causes of ADHD

Scientists are still not able to identify the exact causes of ADHD. However, they are quite sure that ADHD is not caused by brain damage or food allergies. There are several strong and well supported research hypotheses as to the causes of ADHD as follow:

Possible Causes of ADHD

+  Heredity/genetic factors. Many ADHD children have a family member or close relative affected to some 
degree by the problem. These may include either one of their parents or even a first uncle or auntie. If one twin has ADHD, there is a  90% chance the other does too. Hence genetic proclivity (inclination) is by far considered as one of the most common causes of ADHD.

+  Neurotransmitter deficit. Neurotransmitters are chemicals in the brain that pass information from one cell to another. The brain houses many neurotransmitters but two of them - noradrenaline and dopamine - appear to play lead roles in the regulation of arousal and attention. It is not possible to do direct research on the influence that noradrenaline and dopamine have on children’s behaviours, but there is some evidence that supports the suggestion that they have a role to play. The intake of stimulant medication do affect the regulation of these two neurotransmitters.

+  Underdeveloped arousal systems in the brain. Because stimulant medication do increase arousal, this led

some researchers to ponder that perhaps ADHD children suffer from under-arousal which makes them insensitive to incoming stimuli. Their hyperactivity may reflect stimulus seeking instead of over stimulation.

+  Abnormal brain development. Probably due to dysfunctional frontal lobes. These are the areas of the brain that control executive functioning (planning, organizing, starting, persisting, shifting and inhibiting implusive behaviours).

+ Research conducted on people with ADHD showed that certain parts of their brain have less activity and blood flow. Also noted was that some of their brain structures were slightly smaller. These differences in brain activity and structure are mainly evident in the prefrontal cortex, the basal ganglia, and the cerebellum. These areas relate to mood control, behaviour, and attention span.

However, because the exact causes of ADHD remains clouded in mystery, other possible causes being bandied about or still under investigation include factors such as premature birth, iron-deficiency anemia, lead exposure, exposure to environmental toxins, and even watching television. According to one study, children who are exposed to heavy television viewing may exhibit ADHD-like problems in later years. They recommend that children, especially those under two years old, should not be exposed to watching television too much.

However, findings from a recent two-year study conducted by Texas Tech University in Lubbock brushed aside the suggestion which listed watching television as one of the possible causes of ADHD. The researchers also pointed out that ADHD has been around way before children had television to watch.

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