The second half of the 20th century also saw the development of biochemical hypotheses for schizophrenia. The most prominent was the dopamine hypothesis that Carlsson and Lindqvist originally put forth in 1963; it was based on the biochemical effects of treatment with the first antipsychotic drugs, which had been introduced only in 1952. Animal studies lent support to what became a building block of antipsychotic drug discovery - the search for dopamine receptor blockers - and treatment, and Carlsson shared a Nobel Prize for this and other research in 2002.
At this time multiple classes of dopamine receptors are known. Genetic mutations in dopamine receptors have also been discovered and have been applied to comparisons of patients and controls for decades. At first there appeared to be no association between these genetic changes and susceptibility to schizophrenia, but as evidence accumulated from studies of thousands of normal controls and patients ...
