During the last 30 years, several studies in psychiatric genetics have been conducted. These include a series of clinical and family-oriented studies on genetic factors in schizophrenia, alcoholism, and manic-depressive disorder. Since these trials have taken place, great emphasis has been placed on the hypothesis that psychiatric disorders could have a genetic vulnerability. This hypothesis is supported by significant advancements in biological and mathematical analysis methods, as well as by the large number of epidemiological and diagnostic studies on the prevalence of psychiatric disorders in patients' families. This article provides on overview of this research.
Many other hypotheses have been raised by the optimism of research, but are often followed by experimental failures. There are several pitfalls in methods, ranging from sample selection to genotyping to statistical analysis methods. Finally, the interpretations of the results often have been misunderstood. Nonetheless, this body of research contributes to future genetic perspectives in psychiatry.