ADHD News & Research

Study: Adults with OCD and Comorbid ADHD Comprise an Important Subgroup

Adult patients with both OCD and comorbid ADHD exhibit unique clinical characteristics including earlier symptom onset, increased risk for academic impairment, and increased prevalence of Tourette’s Syndrome, according to a new Brazilian study.

April 30, 2019

Adults with obsessive compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD or ADD) present significantly unique symptoms, making them an important subgroup of OCD patients, according to a study published in Depression and Anxiety1 by researchers from the Department of Psychiatry at the Federal University of São Paulo, Brazil.

According to data gathered from 955 adults with OCD from the Brazilian Research Consortium of Obsessive Compulsive Spectrum Disorders, patients with comorbid ADHD experienced earlier onset and more severe symptoms of OCD. Researchers used Fisher’s exact test, t‐tests, or Mann‐Whitney tests to compare clinical characteristics of patients and to determine that the following was true for those with OCD and ADHD (13.7% of the population studied):

  • were younger
  • had earlier onset of OCD symptoms
  • had an increased risk for academic impairment
  • had a higher number of current and lifetime comorbidities
  • had an increased rate of Tourette’s syndrome
  • had greater anxiety and depression symptom severity
  • had more suicide attempts
  • had higher symptom severity in most DY-BOCS dimensions
  • experienced sensory phenomena more frequently

These findings demonstrate the need for further investigations into the ways in which an ADHD comorbidity may influence OCD symptoms in adults so that medical professionals can begin to tailor interventions accordingly, the researchers wrote.


Thiago Blanco‐Vieira, Matheus Santos, Ygor A. Ferrão, Albina R. Torres, Eurípedes C. Miguel, Michael H. Bloch, James F. Leckman, Maria C. do Rosario. The Impact of Attention Deficit Hyperactivity Disorder in Obsessive-Compulsive Disorder Subjects. Depress Anxiety (Apr. 2019).