Disorders usually first appearing in infancy, childhood, or adolescence. Any deviation from normal development, including mental retardation, autism, attention deficit disorder with hyperactivity, excessive fears, speech problems, and highly aggressive behaviour. Delirium, dementia, amnestic, and other cognitive disorders. Disorders due to deterioration of the brain because of aging disease (such as alzheimer"s disease) or ingestion or exposure to drugs or toxic substances (such as lead). Psychological, social, or physical problems related to abuse of alcohol or other drugs, not including symptomless recreational use. A group of disorders marked by loss of contact with reality, illogical thought, inappropriate displays of emotion, bizarre perceptions and usually some form of hallucinations, or delusion. Disorder involving extreme deviations from normal mood, including severe depression (major depression), excessive elation (mania), or alternation between severe depression and excessive elation (bipolar disorder). Disorders involving pain, paralysis, or blindness for which no physical cause can be found.