Abstract
OBJECTIVE: Early identification of substance use during adolescence is imperative to reduce the risk of morbidity and mortality. The aim of this study was to determine the utility of the Global Appraisal of Individual Needs-Quick Version 4 (GAIN-Q4) at diagnosing substance use disorders (SUDs) in adolescents. METHODS: The GAIN-Q4 was developed from the GAIN-Quick Version 3 by adding items from the original measure (GAIN-I) to diagnose SUDs and provide level of care recommendations. Prevalence, sensitivity (SE), specificity, Cohen's kappa, and percent agreement between the GAIN-I and GAIN-Q4 were calculated for substance use and mental health (MH) diagnoses. The GAIN-I was administered to adolescents aged 12-17 and adults across levels of care and service settings from 2002 to 2018. The sample included 101,897 adolescents (71.50% male; average age 15.59, SD = 1.25 years) and 204,711 adults aged 18 and older (61.72% male; average age 34.24; SD = 11.67). RESULTS: Nearly half of adolescents (43%) had at least one SUD and one MH diagnosis based on the GAIN-Q4. The sensitivity and specificity of the GAIN-Q4 for diagnosing any SUD in adolescents was 89% and 93%, respectively. There was 90% agreement between the GAIN-Q4 and GAIN-I for any SUD (Cohen's kappa of 0.80). Sensitivities for all SUD subtypes were >90%. CONCLUSIONS: The GAIN-Q4 is excellent at identifying adolescents with problems related to co-occurring MH and SUDs (SE = 97%). The GAIN-Q4 is a reliable instrument for the diagnosis of SUDs in adolescents and has the potential to facilitate appropriate allocation of treatment resources. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05001399.