Among personality disorders, dependent personality disorder increased the probability of treatment of alcohol dependence, schizoid personality disorder was associated with increased treatment of drug abuse, and avoidant personality disorder increased the probability of treatment for drug dependence. By contrast, narcissistic personality disorders lowered the probability of treatment of alcohol abuse and antisocial personality disorder lowered the probability of treatment of drug dependence (Table 4). VIFs for all variables in the multivariable model were less than two, indicating there were not substantial collinearity problems in the estimations.
