Memantine Augmentation in a Down's Syndrome Adolescent with Treatment- Resistant Obsessive-Compulsive Disorder.

[Author Affiliation]Scott R. Pekrul. Department of Child and Adolescent Psychiatry, University of Michigan Ann Arbor, Michigan.Kate D. Fitzgerald. Department of Child and Adolescent Psychiatry, University of Michigan Ann Arbor, Michigan.Address correspondence to: Scott R. Pekrul, MD, Department of Psychiatry, University of Michigan, 4250 Plymouth Rd. SPC 5766, Ann Arbor, MI 48109, E-mail: scottpek@med.umich.eduTo The Editor:Down's syndrome (DS) is a chromosomal disorder that is the most frequent cause of intellectual disability (mental retardation [MR]). Psychiatric comorbidity is relatively common in the Down's population, and is estimated to range from 18% to 38% (Prasher and Day 1995; Capone et al. 2006). Although little research has been completed with obsessive-compulsive disorder (OCD) in DS populations, it is estimated to occur in from 0.8% to 4.5% of patients (Prasher and Day 1995; Capone et al. 2006). OCD is characterized by intrusive thoughts, images, or urges (obsessions) with purposeful mental or physical actions (compulsions) aimed at reducing anxiety caused by the obsession. OCD in DS patients is postulated to present more often with compulsive behaviors of ordering and tidiness, such as rearranging personal belongs or opening/closing doors, cabinets, blinds, and light switches (Prasher and Day 1995; Capone et al. 2006), driven by "just right" obsessions (Charlot et al. 2002).First-line pharmacological treatment for OCD in nondevelopmentally disordered populations is a serotonin reuptake inhibitor (SSRI), which is effective in 40-60% of cases (Pediatric OCD Treatment Study [POTS] Team 2004; Abudy et al. 2011). Various strategies for treatment-resistant OCD include switching to another SSRI, augmentation with antipsychotics, or the use of a serotonin norepinephrine agent (Abudy et al. 2011). More recently, there is emerging evidence that glutamatergic agents such as memantine are effective in treatment-resistant OCD in both adult and pediatric OCD patients (Pasquni and Bodni 2006; Aboujaoude, Barry, Gamel, 2009; Hezel et al. 2009; Stewart et al. 2010). Given that memantine has demonstrated effectiveness in treatment-resistant OCD in nondevelopmentally disabled patients, it may be helpful in DS populations with OCD. Here, we report on a case using memantine in an adolescent with DS and OCD.Case ReportN was a 16-year-old Caucasian male with a history of DS and mild MR who presented to a university-based child/adolescent psychiatry clinic with his biological parents for evaluation of obsessive behaviors. N had had no prior psychiatric history until age 14 when he developed "just right" rituals. His symptoms were characterized by compulsively turning off lights; insisting that all doors needed to be shut; as well as aligning books, pictures, boxes, and sunglasses so they were "just so." He also displayed hoarding behaviors such as keeping water bottles, sunglasses, and boxes. If a family member closed a door, turned on a light, or misarranged his items, he became very upset and agitated. He would engage in these behaviors up to 8 hours per day, causing significant distress in the home.N was evaluated by a community psychiatrist who diagnosed him with OCD and initiated sertraline. He quickly developed agitation, anxiety, and increased compulsive behaviors. The medication was discontinued and changed to risperidone. On risperidone (dose unknown), he showed no change in symptoms and developed weight gain and drooling. Risperidone was then changed to aripiprazole, which he was on for several months before being evaluated at the university-based child/adolescent clinic.At the university clinic evaluation, his parents reported that aripiprazole decreased his symptoms "somewhat" but that nonetheless the symptoms continued to cause significant distress. Given his minimal response and a 9.1 kg weight gain, it was tapered off. Another trial of an SSRI was agreed upon, and fluoxetine was initially titrated to 20 mg. …