Study 09 – Differentiation of Phenotypes for Smoking: Administrative Supplement to Join NIDA Genetics Consortium

Investigators:  Ovide Pomerleau, Cindy Pomerleau

Release Date:  Available at NIDA

Summary

This project builds on NIDA grant R01 DA06529, which was designed to provide accurate identification and characterization of two important phenotypes by partitioning the effects of 1) nicotine dependence and 2) depression, using baseline data as well as laboratory testing of behavioral, physiological, and neuroendocrine response to smoking abstinence.  The parent project involves recruitment of 280 current smokers and sorted into four groups based on nicotine dependence and depression:

  1. high nicotine dependence and high depression
  2. high nicotine dependence and low depression
  3. low nicotine dependence and high depression
  4. low nicotine dependence and low depression

An administrative supplement from NIDA allows for collection of comparable baseline data from 280 never-smoker case controls, matched with the smokers for age (within a decade), race, gender and depression category, and enrollment of all participants in the NIDA Genetics Consortium.  The supplemental project sets the stage for a critical test of whether unique genetic differences can be identified to explain observed phenotypic differences in nicotine dependence and depression (as evinced by presence or absence of polymorphisms for alleles involved in the control and expression of nicotine receptors, nicotine metabolism, and dopaminergic activity). 

All participants will be between the ages of 25-65, in good medical health, and not taking antipsychotic or antidepressant medications.  For smokers, the Fagerstrom Test of Nicotine Dependence (FTND; Fagerstrom et al., 1991; Heatherton et al., 1991; Pomerleau et al., 1994) will be used to determine presence or absence of nicotine dependence (FTND > 4 and FTND < 4 respectively).  Scores on the Center for Epidemiological  Studies-Depression Scale will be used to define high depression status (CES-D > 16) and low depression status (CES-D < 16).  DSM-IV diagnoses will be established using a computerized version of the Composite International Diagnostic Interview (CIDI; WHO, 1997), version 2.1, a structured interview developed by the World Health Organization, NIMH, NIAAA, and NIDA to provide a comprehensive, fully standardized instrument to assess mental disorders consistent with definitions and criteria of the ICD-10 (WHO, 1992; 1993) and the DSM-IV (APA, 1994).  Modules to be used in all participants are tobacco, alcohol, depression, mania, and other substance use.  Participants classified as low depression using a CES-D < 16 must also have no lifetime CIDI diagnosis of Major Depressive Disorder.  Smoking status is verified via NicCheck test strips (DynaGen, Inc.) that detect the presence of nicotine and its metabolites in urine.

Links

Composite International Diagnostic Interview

CIDI website