phenocopy

Full Definition

In psychiatric epidemiology, a phenocopy refers to a clinical presentation that closely resembles a genetically determined psychiatric condition but arises from environmental, toxic, or acquired causes rather than inherited genetic factors. Phenocopies complicate genetic epidemiological studies by introducing misclassification bias and can lead to underestimation of heritability. Common examples include substance-induced psychosis that mimics schizophrenia, or medical conditions that produce depression-like symptoms.

Usage

Usage note: Important consideration in genetic epidemiology studies.

In Context

• "Thyroid dysfunction can present as a phenocopy of major depressive disorder." — differential diagnosis discussion
• "The study excluded potential phenocopies by screening for medical causes of psychiatric symptoms." — methodology section