Emerging adulthood is a unique developmental stage during which significant transitions in living environment, social networks, personal responsibilities, and identity development occur. Stress associated with these transitions relates to increases in health-risk behaviors, such as substance use and high-risk sexual behavior. This research examined health-risk behavior outcomes associated with the Young Adult Family Check-Up (YA-FCU). The YA-FCU comprises three sessions: an initial interview, an ecological assessment, and a feedback session that integrates motivational interviewing (MI) techniques. This study measured treatment fidelity of the YA-FCU and the extent to which therapists adhered to principles of MI during feedback sessions. Therapists included both licensed psychologists and trainees. The study also examined the relationship between therapists' MI fidelity and client change talk (CT), in order to determine if MI fidelity and client CT predicted postintervention health-risk behaviors among emerging adults who participated in the YA-FCU. Measures of health-risk behaviors were collected pre- and post- intervention. Results indicated overall adequate treatment fidelity. MI fidelity was positively related to client CT. Several indicators of MI fidelity predicted decreases in emerging adults' health-risk behaviors. For example, therapist ratio of reflections to questions predicted a decline in emerging adults' alcohol use frequency and marijuana use quantity. These results have important implications for YA-FCU training and implementation and indicate that MI consistent skills might be a mechanism of change in the YA-FCU intervention.

Family-centered prevention is effective at reducing risk behavior throughout the life span and promoting healthy development. Despite research that suggests parents continue to play a significant role in the lives of their children during emerging adulthood, very few studies have examined effective family-centered strategies for preventing risk behavior in young adults. Typical prevention efforts for this age group have focused on college students and substance use prevention, with no integration of families or systems of support that may sustain the effects of the intervention. In this study, we evaluated a version of the Family Check-Up (FCU) that was adapted for young adults and their families, the Young Adult Family Check-Up (YA-FCU). Families were randomly assigned to receive the FCU or school as usual during the middle school years. Ten years later, they were offered the YA-FCU, which was adapted for families of emerging adult children. Intent-to-treat and complier average causal effect analyses were used to examine change in young adult risk behavior approximately 1year after receiving the YA-FCU. Analyses indicated that random assignment alone or simple engagement was not associated with reductions in young adult risk behavior. However, dose-response analyses indicated that the more hours that youth and families were engaged in the YA-FCU, the greater the reductions in young adult risk behavior relative to those who did not engage or engaged very little in the intervention, resulting in a medium effect size of the YA-FCU on risk behavior.