Is ADHD a risk factor for substance abuse

A number of studies have been conducted that show a modest connection between childhood ADHD and risk for later substance abuse (Biederman et al., 2006; Lambert & Hartsough, 1998; Mannuzza et al., 1991; Molina, Flory et al., 2007; Molina, Pelham et al., 2003;2007).  Study findings vary somewhat due to different ages of the participants, different types of samples (children recruited from treatment clinics versus children in large community survey studies), different ways of measuring substance abuse, and differing levels of attention to other problems such as conduct problems that may also be related to substance abuse.  Across a number of studies, however, there is a recurring pattern of findings that children with ADHD have an increased risk for substance abuse of one form or another.  ADHD also contributes to a faster progression from initial use to abuse, and substance abuse may follow a more aggressive course among individuals with a history of ADHD.

In research studies and media reports, ‘substance abuse’ may mean different things. First, when studying adolescents in general, many studies have shown that early-aged substance use, such as having a full drink of alcohol (not just a taste or a sip) before the age of 15, is associated with an increased risk of heavier or problem drinking later (Grant & Dawson, 1997).  Thus, some studies have specifically examined whether childhood ADHD is associated with early consumption.  One large widely cited study, the Multimodal Treatment of ADHD study (MTA), reported that alcohol, tobacco, and marijuana use was more likely to be initiated by early adolescence in youngsters with ADHD than for classmates in that study who did not have ADHD (Molina et al., 2007).  At older ages, repeated or heavier levels of use become important to study, such as binge drinking of alcohol (Molina, Pelham et al., 2007) or dependence on nicotine and illicit drugs (Biederman et al., 2006; Lambert & Hartsough, 1998; Mannuzza et al., 1991).

As children become older, the way in which substance use is studied changes.   This is because substance use disorders are often considered developmental disorders (Zucker 2006).  An implication of this idea is that risk for substance use among children with ADHD is tied to the age at which the research is being conducted (Molina, Pelham et al., 2007).  This helps to understand why some studies fail to find an increased risk for abuse or dependence in the teenage years (Molina et al., 2003; Biederman et al., 1997).  Conversely, when adolescents or adults with substance abuse or dependence are the subject of study, substantial proportions are often diagnosable with ADHD (Wilens 2008).

Why are children with ADHD at risk

There are a number of plausible reasons for the connection between ADHD and substance abuse (Molina & Pelham, 2003; Wilens & Biederman, 2006).  The core symptoms of ADHD, namely inattention, impulsivity, and hyperactivity, have been known for a number of years to predict substance use in adolescents not diagnosed with ADHD.  These symptoms in and of themselves may increase risk for a number of reasons through the various problems they cause in school, at home, and with friends.  Many of these problems are known risk factors for the development of substance use or abuse. For example, conduct problems such as lying, stealing, and skipping school are more common among children with ADHD and also contribute to the development of substance use (Gittelman et al., 1985; Molina & Pelham, 2003).  Poor school performance increases risk for teenage substance abuse.  ADHD and substance use disorders such as dependence on illicit drugs also tend to run together in families (Biederman et al. 2008).  Each of these problems has strong familial tendencies and they co-occur at greater rates than chance, suggesting that genetic underpinnings may be contributing to their co-occurrence.  A controversial question pertains to the treatment of ADHD with stimulant medications and whether this practice increases risk or protects from risk.  These are but a few of the suspected mechanisms that may underlie the ADHD-substance use connection.

How should this risk be managed

Research is still accumulating to inform best practice, but some general guidelines may be drawn from the literature (Mariani & Levin, 2007; Riggs 1998; Wilens 2008).  Because conduct problems in children are strongly tied to early initiation of substance use and later substance abuse, interventions aimed at minimizing their occurrence have the potential to prevent or delay initiation and ultimately progression.  The MTA found that the children who were assigned to intensive behavior therapy, with or without medication management, were less likely to initiate substance use in early adolescence (Molina et al., 2007).  This finding is encouraging in light of ADHD children’s risk for substance abuse. In other words, prevention of adolescent substance use should involve the early psychosocial treatment of risk factors.  In the MTA study, medication treatment, either study-delivered via random assignment, or self-selected following the completion of the randomly assigned treatments, did not predict this initial early adolescent substance use.  Other studies have reported that stimulant treatment may protect against later substance abuse or dependence for boys (Biederman et al. 1999) and for girls (Wilens, Adamson et al., 2008).  No studies have yet shown that stimulant treatment is associated with worsening of substance use in adolescence (or for that matter, among adults being treated for both substance dependence and ADHD; for review, see Wilens, 2008).

There is a well-developed literature showing that specific types of family therapy as well as cognitive-behavior therapy are efficacious in the treatment of substance abuse with adolescents (Slesnick, Kaminer, Kelly 2008).  These techniques per se have not been demonstrated to be effective for the treatment of ADHD among adolescents, but the treatment literature for adolescents with ADHD is, in general, lacking.  As for adults with substance use disorders and ADHD, a comprehensive evaluation that considers history of symptoms and treatment and full evaluation of ADHD after stabilization of any addictions is warranted (Mariani & Levin, 2007; Riggs 1998; Wilens 2008).  Therapeutic approaches that address motivation, that use cognitive-behavioral strategies, and that facilitate 12-step involvement, have all been shown to be effective for adults with substance use disorders, and there is some support for their use with adolescents as well.  Medication management, to the extent that it has been studied, has not been shown to worsen existing substance abuse problems among individuals seeking treatment for addictions (Wilens 2008).

Tobacco

Perhaps the strongest association between childhood ADHD and later substance use may be found for tobacco use (usually in the form of cigarette smoking).  For example, in one study, 46% of children with ADHD were daily smokers by the age of 17 versus 24% of age-mates without ADHD (Lambert & Hartsough, 1998). Nicotine addiction is a particularly important risk of which parents should be aware given the large and strong associations found across multiple studies and the difficulty of quitting once addiction is full-blown.   Moreover, the strong tendency for cigarette smoking to run in families, and for smoking to be more common among the children of cigarette smokers, should help some parents muster motivation to quit, despite the difficulties of doing so.

For more information on substance abuse and treatment options:

• SAMHSA’s National Clearinghouse for Alcohol and Drug Information (NCADI)
  http://www.samhsa.gov
• National Institute on Alcohol Abuse and Alcoholism
  www.niaaa.nih.gov
• National Institute on Drug Abuse
  www.drugabuse.gov
• SAMHSA Treatment Facility Locator
  https://findtreatment.samhsa.gov/ 
• Coalition to Prevent ADHD Medication Misuse (CPAMM)
  http://www.cpamm.org/