The alcohol consumption of young people with ADHD may be influenced by their peers who consume alcohol. Therefore, this study aimed to determine whether peer alcohol use influences heavy drinking in young people with ADHD beyond the peak period (age 18–25 years) for alcohol use in young adults (Center for Behavioral Health Statistics and Quality, 2015; Derefinko KJ et al, 2016).
The Pittsburgh ADHD Longitudinal Study (PALS) was designed to study individuals with childhood diagnosis of ADHD and predictors of alcohol outcome among this group. Participants in PALS were diagnosed with childhood ADHD (using Diagnostic and Statistical Manual of Mental Disorders [DSM]-IIIR or DSM-IV criteria) between 1987 and 1996. Exclusion criteria for the study included: IQ <80; history of seizures or other neurological problems; and/or any significantly impairing mental disorders. The first measure used in this study was perceived peer alcohol use, where participants were asked how many of their friends they estimated used alcohol (1) occasionally and (2) regularly.* A composite peer alcohol use scale was created with the averaged responses of the two items. The second measure was heavy alcohol use, where participants were asked about their past-year binge drinking frequency.† Baseline demographics were also measured at study entry and used as covariates‡; participants were followed up annually until 2008.
Overall, 597 participants from PALS aged between 18 to 29 years with any data were included in analyses (n = 359 with and n = 239 non-ADHD). The majority of participants were male (89%) and identified as White (non-Hispanic [82%]). Participant demographics included: married by age 29 (15% with ADHD vs 27% non-ADHD; within this group, 3% with ADHD vs 1.5% non-ADHD were divorced); living in parents’ or guardians’ homes (19% with ADHD vs 6% non-ADHD); working full-time (42% with ADHD vs 57% non-ADHD); working part-time (8% with ADHD vs 6% non-ADHD); unemployed (18% with ADHD vs 9% non-ADHD) and had a college degree by age 29 (18% with ADHD vs 62% non-ADHD).
Growth in perceived peer alcohol use and heavy drinking frequency
Perceived alcohol use levels increased between the ages of 18 to 21 years (βADHD = 0.61, p < 0.05; βnon-ADHD = 0.62, p < 0.05). However, between the ages of 21 to 29 years there was a significant decline in perceived alcohol use (βADHD = –0.48, p < 0.01; βnon-ADHD = –0.59, p < 0.01). Additionally, heavy drinking frequency significantly increased from ages 18 to 21 years (βADHD = 0.76, p < 0.01; βnon-ADHD = 0.81, p < 0.01) and significantly declined from ages 21 to 29 years (βADHD = –0.39, p < 0.05; βnon-ADHD = –0.39, p < 0.05). The perceived peer alcohol use and the heavy drinking in participants were significantly related to gender (peer use: βADHD/non-ADHD = –0.12, probability of superiority [ps] < 0.05; heavy drinking: βADHD/non-ADHD = –0.18, ps < 0.001), race (peer use: βADHD/non-ADHD = –0.13 to –0.14, ps < 0.05; heavy drinking: βADHD/non-ADHD = –0.20 to –0.21, ps < 0.001), and childhood conduct disorder and oppositional defiant disorder (peer use: βADHD/non-ADHD = –0.02 to –0.12, ps < 0.05; heavy drinking: βADHD/non-ADHD = –0.02 to –0.12, ps < 0.01).
ADHD versus non-ADHD group differences
When participants were aged between 18 and 21 years, the frequency of heavy drinking was significantly higher for those with ADHD (p < 0.05). At 29 years, non-ADHD individuals exhibited higher perceived peer alcohol use (β = 4.12, p < 0.001) than the ADHD group (β = 3.78, p < 0.001). Only individuals with ADHD had a positive association between perceived peer alcohol use (when aged 18 to 21 years) and heavy drinking frequencies at age 29 years (p < 0.05). Individuals with ADHD who reported more peers using alcohol between ages 18 and 21 years typically experienced more frequent heavy drinking at 29. Perceived alcohol use between 21 to 29 years in non-ADHD individuals was positively associated with an individual’s heavy drinking frequency at age 29 years (p < 0.01). For individuals with ADHD there was a decline in perceived peer alcohol use between ages 21 to 29 years, which was unrelated to heavy drinking at age 29 years. There was positive association between perceived peer alcohol use (between 18 and 21 years) and heavy drinking frequency (between 21 and 29 years) for individuals with ADHD, while it was negative for non-ADHD individuals (p < 0.05). Therefore, individuals with ADHD who perceived increased peer alcohol use between 18 and 21 years typically decreased less than non-ADHD individuals in their own heavy drinking frequencies from 21 to 29 years (βADHD = 0.22, p = 0.13; βnon-ADHD = –0.08, p = 0.54).
There were several limitations of this study. For example, there was limited racial and gender diversity within the sample. The findings may not relate to the broader ADHD population as participants were clinically referred and took part in a summer treatment programme in childhood. Also, as heavy drinking frequency was only measured with a single item there may be potentially questionable reliability.
In summary, this study showed that peer alcohol use changed in tandem with an individual’s own heavy drinking between ages 18 and 29 years. Results from this study suggested the possibility of a riskier pathway to drinking outcomes in individuals with ADHD based on differences versus non-ADHD individuals. Firstly, faster escalation in heavy drinking frequency between ages 18 and 21 years in the ADHD group. Secondly, there was an association between frequent heavy drinking at age 29 years and increasing perceived peer alcohol use from ages 18 to 21 years in the ADHD group only. Thirdly, individuals with ADHD did not follow the declining and maturing out processes of non-ADHD individuals between ages 21 and 29 years. The authors recommended that interventions that target selection of social contexts by individuals with ADHD may be required to prevent worsening patterns of heavy drinking by the end of early adulthood.
*Response options were ranged on a 5-point scale from 1 (none) to 6 (all)
†Participants were asked, “In the past 12 months, how often did you drink five or more drinks when you were drinking?”. Answers ranged on a 12-point scale from 0 (not at all) to 11 (several times a day)
‡Covariates included gender, race, the highest educational level achieved by the participant’s parents at baseline and whether the participant met diagnostic criteria for conduct disorder or oppositional disorder at baseline
Center for Behavioral Health Statistics and Quality (2015). 2014 National Survey on Drug Use and Health: Detailed Tables. Substance Abuse and Mental Health Services Administration (SAMHSA), Rockville, MD. Available at: https://www.samhsa.gov/data/report/results-2014-national-survey-drug-use-and-health-detailed-tables Accessed October 2020.
Derefinko KJ, Charnigo RJ, Peters JR, et al. Substance use trajectories from early adolescence through the transition to college. J Stud Alcohol Drugs 2016; 77: 942-935.
Kennedy TM, Walther CAP, Pederson SL, et al. Beers with peers: childhood ADHD and risk for correlated change in perceived peer and personal alcohol use across young adulthood. Alcohol Clin Exp Res 2020; Epub ahead of print.