The Implications of Genetic Studies of Major Mood Disorders for Clinical Practice

Background: This article is a selective reviewand synthesis of relevant research findings from genetic studiesof major mood disorders and the application of these to clinicalpractice.

Method: The article discusses the application ofgenetic research findings in major mood disorders, includingepidemiologic and family study risk estimates, risk modifiers,and the concepts of etiologic and phenotypic heterogeneity, to 3clinical domains: risk counseling, diagnosis, and treatmentprediction.

Results: Epidemiologic and family studies haveprovided general risk estimates useful in counselingmood-disordered patients and their relatives. A complete andaccurate family pedigree provides more individualized riskestimates for specific cases and is useful in identifying thephenotypic spectrum of the disorder being transmitted in thefamily. Both proband course parameters and familial loading forpsychiatric illnesses may be relevant for the prediction oftreatment response. However, the hypothesis of inheritedpharmacologic selectivity remains to be proven.

Conclusion: Genetic studies of mood disordershave not yet provided conclusive evidence of specificsusceptibility genes or their pattern of inheritance. However,they have generated information that is useful to clinicalpractice.