Background: Alterations of the γ-aminobutyric acid (GABA) system have been implicated in the pathophysiology of major psychoses. Objective: Restriction fragment length polymorphisms associated with the human γ-aminobutyric acid type A (GABAA) β2 and GABAA γ2 subunit genes on chromosome 5q32-q35 were tested to determine whether they confer susceptibility to major psychoses. Methods: Thirty-two schizophrenic fami...