Searching for valid psychiatric phenotypes: discrete latent variable models.
BACKGROUND
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.
Leoutsakos
Jeannie-Marie S
JM
Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA. jeannie-marie@jhu.edu
Zandi
Peter P
PP
Bandeen-Roche
Karen
K
Lyketsos
Constantine G
CG
D039721:Diagnostic and Statistical Manual of Mental Disorders; D005500:Follow-Up Studies; D006801:Humans; D001523:Mental Disorders / Q000145:classification* / Q000175:diagnosis*; D010641:Phenotype; D011569:Psychiatric Status Rating Scales; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D054928:Validation Studies as Topic