Pharmacological treatment for Attention Deficit Hyperactivity Disorder (ADHD) in children with comorbid tic disorders

Background Attention Deficit Hyperactivity Disorder (ADHD) is the most prevalent of the comorbid psychiatric disorders that complicate tic disorders. Medications commonly used to treat ADHD symptoms include the stimulants methylphenidate and amphetamine; non-stimulants, such as atomoxetine; tricyclic antidepressants; and alpha agonists. Due to the impact of ADHD symptoms on the child with tic disorder, treatment of ADHD is often of greater priority than the medical management of tics. However, for many decades clinicians have been reluctant to use stimulants to treat children with ADHD and tics for fear of worsening their tics. Objectives To assess the effects of pharmacological treatments for ADHD on ADHD symptoms and tic severity in children with ADHD and comorbid tic disorders. Search strategy We searched CENTRAL (The Cochrane Library 2009, Issue 4), MEDLINE (1950 to July 2009), EMBASE (1980 to July 2009), CINAHL (1982 to July 2009), PsycINFO(1806 to July Week 4 2009) and BIOSIS Previews (1985 to July 2009). Dissertation Abstracts (searched via Dissertaation Express), and the metaRegister of Controlled Trials were searched (30 July 2009). Selection criteria We included randomized, double-blind, controlled trials of any pharmacological treatment for ADHD used specifically in children with comorbid tic disorders. We included both parallel group and cross-over study designs. Data collection and analysis Two authors independently extracted data using standardized forms. Main results We included a total of eight randomized controlled studies in the review but were unable to combine any of these in meta-analysis. Several of the trials assessed multiple agents. Medications assessed included methylphenidate, clonidine, desipramine, dextroamphetamine, guanfacine, atomoxetine, and deprenyl. All treatments, with the exception of deprenyl, were efficacious in treating symptoms of ADHD. Tic symptoms improved in children treated with guanfacine, desipramine, methylphenidate, clonidine, and the combination of methylphenidate and clonidine. Fear of worsening tics limited dose increases of methylphenidate in one study. High dose dextroamphetamine appeared to worsen tics in one study, although the length of this study was limited. Authors' conclusions Methylphenidate, clonidine, guanfacine, desipramine and atomoxetine appear to reduce ADHD symptoms in children with tics. Although stimulants have not been shown to worsen tics in most people with tic disorders, they may nonetheless exacerbate tics in individual cases. In these instances, treatment with alpha agonists or atomoxetine may be an alternative. Although there is evidence that desipramine is effective for both tics and ADHD in children, safety concerns will likely continue to limit its use in this population.