Pharmacologic treatments of ADHD
My previous post summarized the epidemiology, causes of ADHD. In this blog post, I review the efficacy and adverse effects of conventional pharmacologic treatments of ADHD. Subsequent posts will discuss the evidence for non-pharmacologic treatment strategies including natural supplements, EEG biofeedback, and others.
Stimulants: efficacy and adverse effects
Stimulant medications are the standard Western treatment of ADHD; however, serotonin-selective reuptake inhibitors (SSRI) and other antidepressants are also used with varying degrees of success. Extended-release forms of stimulants are better tolerated and less often lead to abuse. Rates of stimulant abuse may be especially high in individuals with comorbid conduct disorder or substance abuse. Stimulant use in these populations should be carefully monitored or avoided. Long-acting stimulants are associated with relatively less abuse because they cross the blood-brain barrier more gradually than immediate release stimulants. The recently introduced long-acting stimulant lisdexamfetamine dimesylate is a pro-drug with comparable efficacy to existing long-acting stimulants but with less abuse potential as it must be metabolized in the gut before being converted into the active drug d-amphetamine.
Approximately one-third of children and adolescents who take stimulants experience significant adverse effects, including abdominal pain, decreased appetite and insomnia, and 10% experience serious adverse effects. Because stimulants are classified as scheduled or restricted medications (depending on the country), prescriptions are usually limited to a short supply; this can result in treatment interruptions and transient symptomatic worsening when refills are not obtained on time. One-third of all individuals who take stimulants for ADHD report significant adverse effects, including insomnia, decreased appetite, and abdominal pain. Sporadic cases of stimulant-induced psychosis have been reported. Neurotoxic effects associated with long-term stimulant use have not been fully elucidated; however, chronic amphetamine use in childhood is associated with slowing in growth. Stimulants and other conventional treatments of adult ADHD may be only half as effective as they are in children. Only long-acting stimulants have been approved by the FDA for treatment of adult ADHD however short-acting stimulants are the most prescribed conventional treatments in this population.
Non-stimulant medications: efficacy and adverse effects
Controlled-release stimulants, buproprion, and the SSRI antidepressants are being increasingly used in the adult ADHD population; however, research findings suggest these medications may not be as efficacious as stimulants. Atomoxetine, a selective norepinephrine reuptake inhibitor (SNRI), is the only non-stimulant drug that has been approved by the FDA for adults diagnosed with ADHD. Atomoxetine has less potential for abuse but may not be as efficacious as stimulants. Atomoxetine is also FDA-approved for the treatment of childhood ADHD, however, there are growing concerns about its adverse effects, including hypertension, tachycardia, nausea and vomiting, liver toxicity and possibly increased suicide risk. In Australia, atomoxetine is registered for use by the Therapeutic Goods Administration. Other non-stimulant drugs recently approved by the FDA for treatment of childhood ADHD include modafinil, reboxetine and the α-2-adrenergic agonists clonidine and guanfacine.
In addition to conventional prescription medications, behavioral modification is a widely used conventional treatment of ADHD in children. Psychotherapy and psychosocial support help reduce the anxiety and feelings of loss of control that frequently accompany ADHD. Some findings support that cognitive-behavioral therapy (CBT) reduces symptom severity in adults diagnosed with ADHD.
To learn about non-pharmacologic treatments of ADHD check out my e-book “Attention Deficit Hyperactivity Disorder: The Integrative Mental Health Solution.”