In Reply Costa and colleagues raise important issues regarding how grooming disorders (GDs) should be optimally treated and classified.
N-acetylcysteine (NAC) showed superiority over placebo as monotherapy in excoriation disorder,1 similar to findings in trichotillomania. However, NAC’s findings in obsessive-compulsive disorder (OCD) are mixed. Two clinical trials reported significant benefits of NAC augmentation over placebo for OCD,2,3 while a third study did not show benefits over placebo.4 As Costa and colleagues suggest, differential pharmacological response across disorders is an important factor when considering diagnostic classification. This is also complicated by differences in study designs, as results may vary when using NAC as augmentation to a selective serotonin reuptake inhibitor rather than a primary intervention.
Leppink EW, Chamberlain SR, Grant JE. How Similar Are the Disorders Included Under the Umbrella of Obsessive-Compulsive Disorder and Related Disorders?—Reply. JAMA Psychiatry. 2016;73(8):877-878. doi:10.1001/jamapsychiatry.2016.1452