CASE 3 Adult ADHD and marijuana use
Mr. C, age 30, presents to a psychiatrist with ongoing complaints of inattention, fatigue, and difficulty staying organized. A self-report screen yields symptoms consistent with adult attention-deficit/hyperactivity disorder (ADHD). Mr. C’s school and job history and collateral history from his wife appear to corroborate his assertion that his symptoms have been lifelong. He later admits to regular marijuana use. After further discussion and full evaluation of his substance use, Mr. C is started on bupropion, titrated to 300 mg/d. After 2 months, despite faithful attendance at appointments and openness about his continued marijuana use, Mr. C’s symptoms remain unchanged. He asks about atomoxetine.
Stimulants
Pros. Despite many clinicians’ hesitance to prescribe controlled substances to patients with SUDs, psychostimulants should be considered in a variety of scenarios. Although nonstimulant options are available, stimulants consistently have demonstrated superior efficacy over other treatments and remain first-line agents for adult ADHD.20 Methylphenidate, mixed amphetamine salts, lisdexamfetamine, and atomoxetine are FDA-approved for adult ADHD. Both stimulant classes (methylphenidate and amphetamine-based products) are equally effective for ADHD. In addition, stimulants are used to treat narcolepsy, cognitive disorders such as traumatic brain injury, and as augmentation to antidepressants for MDD.
ADHD affects 5% to 12% of children, and >60% of patients remain symptomatic into adulthood and require continued treatment.21 In particular, problematic inattention may persist throughout adulthood. ADHD does not appear to be an independent risk factor for SUDs in children and adolescents.22 However, substance use increases sharply as ADHD patients enter late adolescence and adulthood, and eventually becomes a problem for 20% of adolescents and adults with ADHD. Conversely, 17% to 50% of patients with alcohol, cocaine, or opioid dependence have co-occurring ADHD.23
Withholding ADHD treatment based on concerns about future or increased current substance abuse is unfounded. A meta-analysis of 6 studies that included 674 medicated and 360 unmedicated patients with ADHD who were followed at least 4 years demonstrated that childhood treatment of ADHD with stimulants reduces the risk of developing alcohol and other drug disorders in adulthood.24 Regarding the effect stimulants have on active substance use, a 12-week, double-blind, randomized controlled trial of 48 cocaine-dependent adults with ADHD showed methylphenidate did not change cocaine abuse or craving, but did improve ADHD symptoms.25
Clinicians also must assess whether untreated ADHD symptoms impair patients’ work or other activities. Driving is a particular concern because ADHD is associated with risky driving habits, motor vehicle accidents, traffic violations, and driving license suspensions.26 In a study that administered cognitive tests to 27 adults with ADHD, methylphenidate treatment improved cognitive performance related to driving (eg, better visual-motor coordination under high-stress conditions, improved visual orientation, and sustained visual attention).27 It is likely this effect could be generalized to other activities where safety is important. Finally, appropriate stimulant treatment may improve participation in rehabilitative programs.
Cons. Despite their positive effects, stimulants can have adverse effects and consequences.28 In routinely prescribed dosages, methylphenidate and amphetamines can cause symptoms related to sympathetic activation, including anxiety, tics, anorexia/ weight loss, and sleep disturbance. A 5-year study of 79 school-age children prescribed methylphenidate, dextroamphetamine, or pemoline, which is no longer available in the United States, showed a significant association between adherence to stimulants and persistence of physiological (eg, headaches, insomnia, anorexia) and mood-related (eg, irritability, dysphoria) side effects.29 Stimulants’ sympathomimetic properties also can lead to dangerous drug-drug interactions with monoamine oxidase inhibitors. For both methylphenidate and amphetamines, overdose can lead to seizures, cardiac toxicity, dysrhythmias, and hyperthermia. All stimulants carry an FDA “black-box” warning that lists increased risk of cardiac complications, sudden death, and psychiatric complications such as psychosis or mania.30
Special considerations. All stimulants have potential for diversion or abuse. Pay close attention to these issues, especially in vulnerable populations and situations where rates of abuse and diversion are elevated. Among college students, white patients, fraternity/sorority members, and individuals with lower grade point averages may be at higher risk for nonmedical stimulant use.31 Adults who misuse or divert stimulants commonly have a history of substance abuse and conduct disorder.32 Short-acting stimulants are abused 4 times more often than extended-release preparations.33
If your ADHD patient has active substance use, be clear that continued substance use is likely to limit stimulants’ effectiveness. In patients who are actively using substances, it will be difficult to disentangle apparent nonresponse to stimulants from the negative cognitive effects of substance use.