SSADDA scores used as dependent variables in study analyses included indices selected to represent: (a) severity of cocaine use, and (b) use of treatment or self-help resources for cocaine dependence. Continuous measures of cocaine use severity included: number of days during the period of heaviest cocaine use; age of first heavy use of cocaine; and number of lifetime (a) withdrawal symptoms, and (b) cocaine dependence symptoms excluding withdrawal. Withdrawal and dependence symptoms were separated based on prior evidence that cocaine withdrawal symptoms are associated with more severe dependence (Sofuoglu et al., 2003). Dichotomous measures included history of cocaine overdose or arrest related to cocaine use. Finally, dichotomous scores were used to assess the utilization of services or supports for cocaine dependence, including any receipt of cocaine dependence treatment and any attendance in cocaine dependence self-help support programs.
