title: Common psychiatric disorders and caffeine use, tolerance, and withdrawal: an examination of shared genetic and environmental effects.
abstract: BACKGROUND
  Previous studies examined caffeine use and caffeine dependence and risk for the symptoms, or diagnosis, of psychiatric disorders. The current study aimed to determine if generalized anxiety disorder (GAD), panic disorder, phobias, major depressive disorder (MDD), anorexia nervosa (AN), or bulimia nervosa (BN) shared common genetic or environmental factors with caffeine use, caffeine tolerance, or caffeine withdrawal.
  
  
  METHODS
  Using 2,270 women from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders, bivariate Cholesky decomposition models were used to determine if any of the psychiatric disorders shared genetic or environmental factors with caffeine use phenotypes.
  
  
  RESULTS
  GAD, phobias, and MDD shared genetic factors with caffeine use, with genetic correlations estimated to be 0.48, 0.25, and 0.38, respectively. Removal of the shared genetic and environmental parameter for phobias and caffeine use resulted in a significantly worse fitting model. MDD shared unique environmental factors (environmental correlation=0.23) with caffeine tolerance; the genetic correlation between AN and caffeine tolerance and BN and caffeine tolerance were 0.64 and 0.49, respectively. Removal of the genetic and environmental correlation parameters resulted in significantly worse fitting models for GAD, phobias, MDD, AN, and BN, which suggested that there was significant shared liability between each of these phenotypes and caffeine tolerance. GAD had modest genetic correlations with caffeine tolerance, 0.24, and caffeine withdrawal, 0.35.
  
  
  CONCLUSIONS
  There was suggestive evidence of shared genetic and environmental liability between psychiatric disorders and caffeine phenotypes. This might inform us about the etiology of the comorbidity between these phenotypes.
authors.affiliation: Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA. jdellava@vcu.edu
authors.forename: Jocilyn E
authors.initials: JE
authors.lastname: Bergin
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Kendler
mesh_terms: D000328:Adult; D000856:Anorexia Nervosa / Q000139:chemically induced* / Q000235:genetics / Q000523:psychology; D001008:Anxiety Disorders / Q000139:chemically induced* / Q000235:genetics / Q000523:psychology; D002032:Bulimia / Q000139:chemically induced* / Q000235:genetics / Q000523:psychology; D002110:Caffeine / Q000009:adverse effects*; D003865:Major Depressive Disorder / Q000139:chemically induced* / Q000235:genetics / Q000523:psychology; D004200:Diseases in Twins / Q000139:chemically induced* / Q000235:genetics / Q000523:psychology; D005260:Female; D059647:Gene-Environment Interaction; D006801:Humans; D016584:Panic Disorder / Q000139:chemically induced* / Q000235:genetics / Q000523:psychology; D010641:Phenotype; D010698:Phobic Disorders / Q000139:chemically induced* / Q000235:genetics / Q000523:psychology; D012042:Registries; D012307:Risk Factors; D013375:Substance Withdrawal Syndrome / Q000235:genetics* / Q000523:psychology; D019966:Substance-Related Disorders / Q000235:genetics* / Q000523:psychology; D014768:Virginia
chemical_list: D002110:Caffeine