AIM:The First Episode Mood and Anxiety Program (FEMAP) is a community-based early intervention program that has been shown to improve health outcomes for emerging adults (EAs) with mood and anxiety disorders. However, not all EAs who are admitted to the program initiate treatment. Our aim was to identify factors that distinguish those who initiated treatment from those who did not. METHODS:FEMAP administered questionnaires to EAs upon first contact with the program, collecting information on a range of socioeconomic, patient and condition-related factors. We compared EAs who initiated treatment in the program (n = 318, 87.4%) to those who did not (n = 46, 12.6%). To examine factors associated with treatment initiation, we specified a parsimonious logistic regression model, using the method of purposeful selection to choose from a range of candidate variables. RESULTS:Anxiety Sensitivity Index - Revised (ASI-R), binge drinking and cannabis use were included in the final logistic regression model. Each one-point increment in the ASI-R score was associated with a 1% increase in the odds of treatment initiation (OR = 1.014; 95% CI [1.003, 1.026]). No other variable was significantly associated with treatment initiation. CONCLUSIONS:Our study provides insight on the differences between EAs with mood and anxiety disorders who initiated targeted treatment services and those who did not. Anxiety sensitivity was significantly associated with treatment initiation at FEMAP. Our findings suggest that it may be anxiety sensitivity, rather than depression or functional impairment per se that drive treatment initiation among EAs.