the dopamine hypothesis

• this explanation suggests that neurons that use the neurotransmitter dopamine, fire too often and transmit too many messages, producing the symptoms of the disorder
• the brain may produce too much dopamine, leading to increased neural activity or that the brain is over-sensitive to dopamine
• it is claimed that excessive dopamine activity contributes to the positive symptoms of schiz
• the hypothesis began with the accidental discovery in the 1950s that the phenothiazines help treat symptoms of schiz
• a side-effect of the phenothiazines was muscle tremors - like those with Parkinson's disease. Parkinson sufferers were known to have abnormally low levels of dopamine
• in the 1960s, it was noted that sufferers of the Parkinson's disease would develop schiz-like symptoms if they took too much L-DOPA (medication that raises dopa levels)