Stimulants are felt to act as a neurotransmitter in certain areas of the brain, correcting a biochemical condition which interferes with attention and impulse control. Often within the first hour after starting treatment, one can see a change in handwriting, talking, attention, improvement in inappropriate activity, non-compliance, and academic performance. Stimulant medications have been shown in many studies to be quite safe and side effects are minimal and mild. Side effects most commonly seen are insomnia, loss of appetite, and weight loss. Other less common side effects include sadness, depression, fearfulness, social withdrawal, sleepiness, headaches, nail biting, and stomach aches.
All side effects are short-term and the majority disappear with a lowering in drug dosage.
Long term studies have found that children treated with stimulant medication do not become addicted, nor does it lead to illegal drug use in later years. Studies have also shown that stimulant may cause some suppression of growth during the first year or two of treatment, but this is a transient problem and any ultimate effects on adult height are minimal. Stimulant drugs are effective in adolescents and adults with ADHD, even though the dosage is the same as in older children. Improvements in behaviour are usually more prominent than improvements in attention. It is felt that tricyclics also act as neurotransmitters but work by improving mood, impulsivity, and frustration tolerance.