Searching for valid psychiatric phenotypes: discrete latent variable models.

INTRODUCTION

A primary challenge in psychiatric genetics is the lack of a completely validated system of classification for mental disorders. Appropriate statistical methods are needed to empirically derive more homogenous disorder subtypes.

METHODS

Using the framework of Robins and Guze's ('Establishment of diagnostic validity in psychiatric illness: its application to schizophrenia', American Journal of Psychiatry, 1970, 126(7), 983-987) five phases, latent variable models to derive and validate diagnostic groups are described. A process of iterative validation is proposed through which refined phenotypes would facilitate research on genetics, pathogenesis, and treatment, which would in turn aid further refinement of disorder definitions.

CONCLUSIONS

Latent variable methods are useful tools for defining and validating psychiatric phenotypes. Further methodological research should address sample size issues and application to iterative validation.