Cocaine addiction involves a host of maddening issues related to psychiatric comorbidity. Perhaps none is more vexing than co-occurring attention-deficit/hyperactivity disorder (ADHD), whether real, misdiagnosed, or malingered.

In this article, I’ll parse through three recurring questions that clinicians confront when treating addiction and ADHD.

ADHD and Addiction

Children and adolescents frequently receive psychostimulants to treat ADHD. Parents and caregivers are often appropriately concerned that these Schedule II (CII) controlled substances are a set-up for addiction later in life. After all, according to the U.S. Drug Enforcement Administration, CIIs are substances that “have a high potential for abuse which may lead to severe psychological or physical dependence” (http://1.usa.gov/1ilYdhS).

Before addressing the risk associated with these medications, we need to consider problems caused by ADHD itself. Various studies have demonstrated that untreated ADHD substantially increases the risk of addiction, even after controlling for other factors. For example, children with ADHD are twice as likely to develop cocaine use disorders during adolescence and adulthood compared to children without ADHD (Lee SS et al, Clin Psychol Rev 2011;31(3):328–341).

Although psychostimulants have considerable abuse potential, a number of studies have found that they actually protect children with ADHD from developing addiction during adolescence (Faraone SV & Wilens TE, J Clin Psychiatry 2007;68(Suppl 11):15–22). In fact, children treated with psychostimulants have about the same risk of abusing substances as those without ADHD. For reasons that aren’t entirely clear, this protective effect burns off when patients age into adulthood.

Clinical Bottom Line: Psycho-stimulants don’t place children with ADHD at risk for later cocaine use and provide some short-term protection from addiction during adolescence.

Addiction as Self-Medication

Edward Khantzian, a psychiatrist at Harvard Medical School, is credited with developing the self-medication hypothesis: that cocaine users are self-medicating to treat another mental disorder (Khantzian EJ, Am J Psychiatry 1985;142(11):1259–1264). He noted that, “cocaine has its appeal because of its ability to relieve distress associated with depression, hypomania, and hyperactivity.” He further observed that cocaine “improve[s] attention leading to improved interpersonal relations, more purposeful, focused activity, and improved capacity for work.”

Khantzian’s argument was light on evidence, relying mainly on case reports and clinical inferences. Nonetheless, his hypothesis gained traction in the professional literature and is still embraced by the lay public today.

In the decades that followed, some suggestive studies emerged. Data obtained from large government surveys found that those who struggled to access mental health services were about twice as likely to use illicit drugs compared to controls (Harris KM & Edlund MJ, Health Serv Res 2005;40(1):117–134). This association seemed to support the idea that people turn to drugs of abuse to cope with unmet service needs.

Mostly, however, the self-medication hypothesis hasn’t panned out (Lembke A, Am J Drug Alcohol Abuse 2012;38(6):524–529). For example, one study followed people with and without ADHD for 10 years. Although those with ADHD had a higher rate of substance use than controls, there were no differences in their motivations for using. Thirty-four percent of people with ADHD reported that they were trying to address psychiatric symptoms, such as problems with mood or sleep, compared to 33% of control subjects (Wilens TE et al, Am J Addict 2007;16(Suppl 1):14–21).

Other studies have looked specifically at patients with dual disorders (both mental illness and addiction). One representative investigation found that cocaine universally worsened primary psychiatric symptoms (Castaneda R et al, Compr Psychiatry 1989;30(1):80–83).

Clinical Bottom Line: There’s little support for the popular notion that cocaine users are self-medicating another mental disorder with cocaine.

ADHD Treatment and Addiction Outcomes

A final challenge is the patient with a bona fide ADHD diagnosis who enters addiction treatment to discontinue cocaine but would like to leave with a prescription for a psychostimulant.

Studies suggest this isn’t the greatest idea. One demonstrated that methylphenidate (such as Ritalin, Concerta, Methylin, Metadate, and Daytrana) improved ADHD symptoms compared to placebo but didn’t reduce cocaine cravings or cocaine use (Schubiner H et al, Exp Clin Psychopharmacol 2002;10(3):286–294).

A similar trial found that methylphenidate neither improved ADHD symptoms nor reduced cocaine use compared to placebo (Levin FR et al, Drug Alcohol Depend 2007;87(1):20–29). A drill down found that patients whose ADHD responded to methylphenidate used less cocaine, however, the reduction in the latter probably wasn’t clinically significant.

Clinical Bottom Line: Psycho-stimulants might improve ADHD symptoms in some cocaine abusers but don’t meaningfully alter the trajectory of their addiction.