Attention deficit/hyperactivity disorder (ADHD) in an adult may be difficult for many primary care providers to treat due to a lack of experience with this diagnosis outside of pediatrics.1 But without treatment, adults with ADHD are more likely to have poor academic and employment records, lower socioeconomic status, higher rates of divorce, more traffic accidents and driver's license suspensions, lower self-esteem, and social difficulties.1 Additionally, the presence of ADHD is a risk factor for the development of substance use disorder (SUD).2
This article focuses on the management of ADHD in adults who also have SUD. The most common treatment for ADHD is stimulant medication, which is generally effective but is associated with a risk for abuse.3 It is important, therefore, to understand the relationship between ADHD and substance abuse and how this affects the treatment of patients with ADHD.3
ADHD and Comorbid SUD
Although SUD is more common in patients with ADHD than in the general population, the etiologic link between the two disorders is unclear.4 Among adults with SUD, rates of ADHD range from 15% to 25%.5 Conversely, approximately 50% of adults with ADHD exhibit SUD.5
Data suggest that for an adult with ADHD, the risk for developing SUD at any time over the lifespan is twice that of adults without ADHD.5 Other studies have determined that young adults with ADHD are four more times likely to exhibit SUD than comparison groups.2 Patients with SUD and ADHD have an earlier onset of substance abuse than those without ADHD, an increased severity of substance abuse, a reduced likelihood of achieving remission, and a tendency to take longer to reach remission.5
Healthcare providers may be uncomfortable diagnosing ADHD in adults due to the dependence on subjective symptoms, the fact that current diagnostic criteria do not describe the subtle differences between symptoms in adults and children, and that some of the most effective treatments involve long-term use of scheduled drugs with potential for abuse.6 As stated, diagnosis and treatment are essential to successful adult functioning.
Diagnostic criteria have been developed for ADHD in children, and they are currently used for the diagnosis of adults.7 ADHD is frequently underdiagnosed in adults, in part because it often presents without the hyperactivity common in the childhood form. ADHD manifestations in adults are generally more subtle and variable. For many years, ADHD was thought to be a childhood condition that did not affect adults.8 But the estimated rate of ADHD persistence into adulthood is now 60%.7 The development of ADHD in adulthood is estimated to be in the range of 2% to 5%.7
The diagnosis of ADHD in adults is further complicated by the overlap between symptoms of adult ADHD and the symptoms of other psychiatric conditions.6 It may be particularly difficult to evaluate and diagnose ADHD when SUD is a comorbid factor.3 Patients seen for depression, anxiety and substance abuse, including nicotine and alcohol addiction, should be screened for ADHD.8 If a patient meets published criteria for symptoms of ADHD, review those symptoms in detail to determine whether they are causing significant impairment of life tasks and whether they date back to childhood.3 Some of the symptoms that prompt adult patients to seek help are poor concentration, disorganization, inability to follow through on job tasks, time management problems, inattentiveness, impulsiveness and temper.8
Concurrent treatment of ADHD and SUD is the optimal approach because ADHD symptoms interfere with SUD treatment and substance abuse limits the benefits of ADHD treatment.7 The treatment of choice for ADHD is psychostimulants.9 The table accompanying this article outlines treatment options.
Animal models have raised concerns that stimulant exposure could produce sensitization and increase the risk for SUD.2 In one study, methylphenidate (MPH) was reliably chosen over placebo; however, the effect tended to be dose-dependent.10 Modern brain imaging studies show that MPH does not cause euphoria at prescribed doses.2 Carpentier9 studied a small number of patients with ADHD and SUD and found a statistically significant reduction in symptoms in patients treated with MPH versus placebo.
Another randomized, controlled study examined the use of MPH in cocaine users and found no increases in cocaine cravings between groups on any of the five subscales of the Tiffany Cocaine Craving Scale.3 The researchers rated 77% of the MPH group as having moderate improvement or better in ADHD symptoms; only 21% of the placebo group experienced improvement.3
In contrast, other studies report that patients treated with stimulants are at a lower risk for substance abuse problems. A recent meta-analysis found that treatment with stimulant medication served a protective function against the development of SUD.11 Most longitudinal studies that followed children whose ADHD was treated with stimulants suggest that stimulant treatment is unlikely to increase the risk of substance abuse.2
Some evidence supports the hypothesis that treatment actually reduces the risk of substance abuse later in life.2 Adolescents who take stimulants for ADHD have a 50% lower risk of developing SUD than those not treated with stimulants.11 Treatment of ADHD with stimulants or other agents might also help patients continue necessary SUD treatment.3 ADHD symptoms, such as impulsivity and impatience might directly result in SUD relapse.3
These findings should reduce fears that stimulants increase SUD risk,3 and they make an important argument against excluding these patients from psychostimulant treatment.9
To reduce the potential for misuse, most clinicians experienced in the treatment of coexisting ADHD and SUD recommend the use of sustained-release stimulants.7 However, clinical data to support this approach is underwhelming.7 Extended-release formulations such as Vyvanse and Concerta offer benefits of convenience, adherence and efficacy.7,8 The crush-resistant shell and the transdermal preparation of Concerta, as well as the prodrug Vyvanse, which is converted to dextroemphetamine in the liver, are more resistant to abuse and may be desirable alternatives in patients with concurrent ADHD and SUD.7
For a patient with a history of substance abuse who is not currently abusing substances and has good functioning, a trial of stimulant medication presents a low-risk intervention.7 Individualized risk assessment should dictate other elements of clinical management, such as the frequency of office visits or urine toxicology screening.7 Factors such as prior history of or ongoing substance abuse, comorbid psychiatric disorders and overall stability should be taken into account.7
When prescribing psychostimulants, make sure the patient is aware that the medication should not be taken on an as-needed basis.7 Dosing should be consistent. Start with a low dose and slowly titrate up until symptoms decrease and behavior improves.12 Monitor closely for adverse effects, including dependence. Side effects can be reduced by decreasing the dose, adjusting the scheduled time, or changing the medication.12 Gastrointestinal disturbances can be managed by dosing 35 to 40 minutes before meals.12 To reduce insomnia, advise patients to take medication earlier in the day.12
More serious side effects, such as arrhythmias, syncope, increased blood pressure, tachycardia, delirium and psychosis, often require immediate attention - as well as discontinuation of the medication.12 If a stimulant medication is misused or abused, it can be discontinued without adverse effects.7 Current abuse of stimulants is an absolute contraindication to stimulant therapy.7
Nonstimulant options are often viewed as a safe alternative for patients with a history of substance abuse because they have not been associated with dependence.10 Choices include atomoxetine (Strattera) and modafinil (Provigil).10 Atomoxetine is the best studied, and it is the only nonstimulant approved by the FDA for the treatment of ADHD in adults.13 It is not a controlled substance and does not require a 30-day limited prescription. Atomoxetine has a longer half-life and requires once-daily dosing; it may be discontinued without tapering.12
Published data suggest that the therapeutic effects of atomoxetine and MPH are comparable.13 The clinical efficacy of atomoxetine in the treatment of ADHD has been evaluated in published clinical trials, which determined that atomoxetine is safe and well tolerated. Data about long-term use are not yet available.14 Atomoxetine is a good alternative for patients who do not respond to or cannot tolerate one or more stimulants, as well as those with comorbid psychiatric diagnoses such as SUD and anxiety.14 Atomoxetine does not require slow titration as the stimulants do.12
Bupropion is widely considered a second-line agent and seems to be well tolerated.13 It can improve ADHD symptoms, but it tends to be less effective than stimulants.13 In a randomized, controlled trial, 76% of patients experienced symptom improvement with bupropion, reporting a 30% reduction in symptoms or more.3
Tricyclic antidepressants (TCAs) are widely considered third-line treatment for ADHD.13 A randomized, controlled trial determined that despiramine was the most effective TCA in adults with ADHD; it produced a response rate of 68%.3 TCAs have the advantages of long half-life, absence of abuse potential and reported positive effects on mood, anxiety, sleep and tics.13 They have a narrow margin of safety and patients must be monitored closely for anticholinergic effects and more serious cardiovascular risks, such as QT interval lengthening and arrhythmias.13
Monoamine oxidase inhibitors (MAOIs) should be considered contraindicated in patients with SUD due to their potential for hypertensive crises associated with tryamine-containing foods and medications.7
An important element of ADHD treatment is psychoeducation. Education about the disorder and its effects on functioning can help set the stage for an effective therapeutic alliance.7 Providing educational literature or referrals to community education or support groups, such as Children and Adults with Attention Deficit Disorder (CHADD) or the Attention Deficit Disorder Association (ADDA), can be useful for patients and families.7
Coaching, organizational training, cognitive behavioral therapy (CBT), psychotherapy and neurofeedback may be useful adjunctive therapies to medication.8 Coaching is a collaborative relationship between the patient and a professional to develop strategies for managing problems such as procrastination, poor time management and poor organization.7 CBT can be effective in reducing symptoms of ADHD in adults.7 In patients who receive CBT for SUD, cognitive deficits such as those associated with ADHD also are associated with low treatment retention. This suggests that retaining patients with cognitive deficits in CBT-based SUD treatment is difficult.7
Above All, Treat
ADHD and SUD commonly occur together in adult patients with ADHD, therefore it is important that primary care providers feel comfortable prescribing appropriate treatment. Untreated ADHD in adults may have significant consequences and interfere with patients' ability to pursue or maintain SUD treatment. Stimulants are the first-line treatment for ADHD, but they do carry a risk for abuse and diversion. It is generally agreed that, for most patients, little concern exists about the use of stimulants in patients with a remote history of substance abuse.3 Many healthcare providers choose a long-acting stimulant or one of the nonstimulant medications to manage ADHD symptoms.3
A conservative approach for treating concurrent ADHD and SUD would be to initiate a nonstimulant medication, such as atomoxetine. If an adequate response is not obtained, proceed to a long-acting stimulant. Based on literature review, providers experienced in the treatment of adult ADHD and comorbid SUD tend to agree that stimulants are an effective treatment with a relatively low risk of abuse in this population. Buproprion and TCAs may be considered as second- and third-line treatments, respectively; they can be helpful, but they are not as effective as stimulants.
All treatment decisions should be made based on the provider's clinical assessment of each patient and with careful monitoring to ensure therapeutic benefit.
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13. Banaschewski T, et al. Non-stimulant medications in the treatment of ADHD. Eur Child Adolesc Psychiatry. 2004;13(Suppl 1):102-116.
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Jennifer L. Patton is a family nurse practitioner at Peninsula Family Medical Center in Gig Harbor, Wash. She has completed a disclosure statement and reports no relationships related to this article.