Various studies place the average age of cataract surgery patients at between 70 and 73. More Info: The incidence of cataracts among Americans is relatively high.
Serotonin. Serotonin is an inhibitory neurotransmitter involved in the regulation of mood, anxiety, libido, compulsivity, headaches, aggression, body temperature, eating disorders, social anxiety, phobias, sleep, appetite, memory and learning, cardiovascular function, muscle contraction, and endocrine regulation.
Attention-Deficit Hyperactivity Disorder (ADHD) appears related to two neurotransmitters - Dopamine and Norepinephrine. Neurotransmitters are used by the brain to stimulate or repress stimulation in brain cells. To pay proper attention, the brain must be adequately stimulated.