Risk of Substance Use in Attention Deficit/Hyperactivity Disorder with Predominately Inattentive Symptoms

Objective: Primary objective of the study was to compare the risk of substance use associated with various attention deficit/hyperactivity disorder (ADHD) subtypes in a large, nationally representative adolescent sample. Secondary objective was to explore the extent of this association being modified by pharmaceutical interventions especially in ADHD with predominately inattentive symptoms (ADHD/I subtype). Methods: National Comorbidity survey-Adolescent supplement (NCS-A), a nationally representative sample of adolescents (age 13-18) was used to assess the wide range of mental disorders and substance use information. Childhood ADHD subtypes and age at onset were calculated retrospectively with the variables of the ADHD DSM-IV criteria symptoms. Substance use information was assessed using the age at first use, frequency of use information about the illicit drugs, alcohol and tobacco. Pharmaceutical intervention and onset of therapy were collected from the parent’s questionnaire about the prescription medication used for relieving the symptoms of ADHD. Association between ADHD subtype and substance use was examined using the multivariate logistic regression analysis. Results: In a nationally representative adolescent sample of US, our study found that individuals with ADHD with predominately hyperactivity symptoms (ADHD/H) and ADHD with predominately hyperactivity and inattention symptoms (ADHD/C) subtype has similar future risk of using substance as ADHD/I subtypes [ADHD/H (OR=0.91, 95% C.I.=0.38-2.17) and ADHD/C (OR=1.49, 95 %CI=0.90-0.34)], after adjusting for socio-demographic factors, comorbid conditions, environmental factors and ADHD pharmacotherapy. ADHD pharmacotherapy is effective in reducing the risk of substance use in ADHD/C and ADHD/H subtype, whereas it was not effective for the purpose in the ADHD/I subtype (in ADHD/I with mood disorder, OR=0.483, 95% C.I.=0.1-2.34, p value=0.36 and in ADHD/I without mood disorder, OR=0.544, 95% C.I.=0.28, p value=0.29). Conclusion: ADHD/I have a significant risk of substance use which is comparable to other subtypes. Still pharmacotherapy is seem to be not effective intervention strategy in ADHD/I subtype. More research is required for examining the effectiveness of behavioral therapy in reducing risk of substance use in the individuals with ADHD/I subtype.