Evidence-Based Reviews

ADHD and substance abuse: 4 therapeutic options for patients with addictions

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Though no head-to-head studies have compared desipramine with methylphenidate, the same researchers conducted a similar placebo-controlled study with methylphenidate. The 6-week symptom score on the ADHD Rating Scale was 12.5 for methylphenidate, compared with a score of 12 for desipramine.18

Recommendation. Desipramine may be the most effective of the antidepressant treatments for patients with ADHD. Because of its side effects, however, it is not this author’s first choice and is usually reserved for patients whose symptoms fail to respond to other antidepressants. Desipramine can cause sedation, dry mouth, and constipation, which are related to blockade of adrenergic, histamine, and muscarinic cholinergic receptors. It also can be lethal in overdose.

Some substance abusers lose confidence in a medication that they cannot feel working. The side effects of desipramine, which can be intolerable for some patients, can reassure others with a history of substance abuse that they are being medicated.

Bupropion

Bupropion is a unique antidepressant that inhibits the presynaptic reuptake of dopamine and norepinephrine. Open-label studies demonstrate good responses to bupropion by adults with ADHD. One placebo-controlled, double-blind study found improved ADHD symptoms in 76% of patients receiving bupropion SR, compared with 37% of those receiving a placebo; the difference was statistically significant.19

Figure 2 IMPROVED ADHD SYMPTOMS WITH DESIPRAMINE


Adults with ADHD who received desipramine, 200 mg/d, in a double-blind trial showed significantly less hyperactivity, impulsivity, and inattentiveness after 6 weeks of therapy than a control group that received a placebo.

Source: Adapted with permission from Wilens TE, Biederman J, Prince J, et al. Six-week, double-blind, placebo-controlled study of desipramine for adult attention-deficit/hyperactivity disorder. Am J Psychiatry 1996;153:1147-53.Another study of adults with ADHD compared bupropion SR to methylphenidate and a placebo.20 Using a primary outcome of the Clinical Global Impression (CGI) scale, response rates were 64% for bupropion SR, 50% for methylphenidate, and 27% for the placebo. The difference in response rates between the two agents was not statistically significant (p = 0.14).

Recommendation. The risk of seizures with bupropion is about 1 in 1,000. Therefore, bupropion should not be given to patients with a seizure disorder or to those with conditions that alter the seizure threshold (e.g., eating disorders, recent head trauma, or benzodiazepine withdrawal).21

This author uses bupropion as first-line treatment for appropriate patients with ADHD and a substance abuse history. Bupropion’s mild benefit with smoking cessation may provide some crossover effect for other substances of abuse. The low incidence of sexual side effects is another benefit. Drawbacks include twice-daily dosing and lack of a robust effect on attention and concentration.

Venlafaxine

Venlafaxine is a potent inhibitor of serotonin reuptake, a moderate inhibitor of norepinephrine, and a mild inhibitor of dopamine. Venlafaxine has displayed response rates similar to those of desipramine and bupropion in open-label studies in adults with ADHD,14 but no placebo-controlled studies exist.

As noted above, these antidepressants are believed to improve ADHD symptoms by making norepinephrine more available at the synapse. Hypothetically, then, one would need to administer venlafaxine at dosages that adequately inhibit the norepinephrine reuptake receptor. Venlafaxine XR, 150 mg/d, provides significant norepinephrine activity, according to several lines of evidence.

Recently, Upadhyaya et al reported the use of venlafaxine in one of the few treatment studies of patients with ADHD and comorbid alcohol/cocaine abuse. In an open-label trial, 10 subjects received venlafaxine, up to 300 mg/d, along with psychotherapy and attendance at Alcoholics Anonymous meetings. The nine who completed 4 weeks of treatment showed significantly improved ADHD symptoms and decreased alcohol craving.22

Recommendation. Venlafaxine is this author’s second choice for patients with ADHD and substance abuse problems. Sexual side effects that some patients experience with venlafaxine can limit its use. Some clinicians are concerned about increases in blood pressure associated with venlafaxine, although significant changes do not seem to occur at dosages below 300 mg/d.23

Atomoxetine

Atomoxetine is an investigational antidepressant in phase-III trials as a treatment for ADHD. Evidence shows atomoxetine to be a potent inhibitor of the presynaptic norepinephrine transporter, with minimal affinity for other neurotransmitter receptors. Initial studies suggest that atomoxetine is effective for adults and children with ADHD:

  • In a small, double-blind, placebo-controlled, crossover trial, 11 of 20 adults showed improvement in ADHD symptoms within 3 weeks of starting atomoxetine.24
  • In 297 children and adolescents, atomoxetine at dosages averaging approximately 1.2 mg/kg/d was more effective than a placebo in reducing ADHD symptoms and improving social and family functioning. Treatment was well tolerated and without significant side effects.25
  • In a randomized open-label trial, 228 children received atomoxetine or methylphenidate. Both treatments significantly reduced inattention and hyperactive/impulsive symptoms.26

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