Externalizing behavior and emotion dysregulation are indicators of transmissible risk for substance use disorder

Background: Psychological items discriminating children of fathers diagnosed with an illicit drug-related substance use disorder and normal controls are indicators of a unidimensional construct termed transmissible liability index (TLI) (Vanyukov et al., 2009). TLI is a highly heritable (Vanyukov et al., 2009; Hicks, Iacono, McGue, 2012) and valid (Vanyukov et al., 2009; Hicks et al., 2009; Kirisci et al., 2013a) measure of childhood liability to substance use disorders (SUDs). Aims: This longitudinal study determined whether TLI has incremental validity for predicting SUD beyond commonly measured psychological indicators of risk. Methods: TLI and measures of executive cognitive capacity, emotion dysregulation and externalizing disturbance were administered to boys at ages 10-12 and 16. SUD outcome determined at age 22 was assessed as (1) any SUD, (2) the number of drug-specific SUDs, and (3) SUD severity. Results: TLI predicted SUD beyond the contribution of measures of emotion dysregulation, executive cognitive capacity and externalizing disturbance. The association of emotion dysregulation and externalizing behavior at ages 10-12 and 16 with SUD at age 22 was also reduced to non-significance after controlling for transmissible risk measured by TLI. Conclusions: TLI's incremental validity beyond these latter indicators of risk points to its utility for identifying vulnerable youths requiring intervention.