We measured nicotine dependence using the Fagerström Test for Nicotine Dependence (FTND), a 6-item questionnaire that assesses various components of smoking behavior such as daily intake, difficulty in refraining from smoking, time to first cigarette, etc. (Fagerström, 1982; Heatherton, Kozlowski, Frecker, & Fagerström, 1991). We also assessed history of major depression using a brief interview consisting of items based on the DSM-IV (American Psychiatric Association, 1994) criteria for a history of major depressive disorder (MDD). This scale was developed and used in our previous studies. Finally, we assessed depressive affect at each visit using the Center for Epidemiologic Studies Depression Scale (CES-D), a 20-item self-report measure developed to assess depressive symptoms in community (non-clinical) populations (Ross and Mirowsky 1984).
