Regression mixture models, which have only recently begun to be used in applied research, are a new approach for finding differential effects. This approach comes at the cost of the assumption that error terms are normally distributed within classes. This study uses Monte Carlo simulations to explore the effects of relatively minor violations of…

Previous research has shown that the development of alcohol and tobacco dependence is linked and that both are influenced by environmental and intrapersonal factors, many of which likely interact over the life course. The present study examines the effects of general and alcohol- and tobacco-specific environmental influences in the family of…