Mistaking OCD for ADHD
Has Serious Consequences

 

Research findings challenge the possibility of comorbidity between these apparently opposite disorders

December 18, 2012, AFTAU —On the surface, obsessive compulsive disorder (OCD) and attention deficit/hyperactivity disorder (ADHD) appear very similar, with impaired attention, memory, or behavioral control. But Professor Reuven Dar of Tel Aviv University's School of Psychological Sciences argues that these two neuropsychological disorders have very different roots—and there are enormous consequences if they are mistaken for each other.

Dar and fellow researcher Amitai Abramovitch, who completed his Ph.D. under Dar's supervision, have determined that despite appearances, OCD and ACHD are far more different than alike. While groups of both OCD and ADHD patients were found to have difficulty controlling their abnormal impulses in a laboratory setting, only the ADHD group had significant problems with these impulses in the real world.

According to Dar, this shows that while OCD and ADHD may appear similar on a behavioral level, the mechanism behind the two disorders differs greatly. People with ADHD are impulsive risk-takers, rarely reflecting on the consequences of their actions. In contrast, people with OCD are all too concerned with consequences, causing hesitancy, difficulty in decision-making, and the tendency to over-control and over-plan.

Their findings, published in the Journal of Neuropsychology, draw a clear distinction between OCD and ADHD and provide more accurate guidelines for correct diagnosis. Confusing the two threatens successful patient care, warns Dar, noting that treatment plans for the two disorders can differ dramatically. Ritalin, a psychostimulant commonly prescribed to ADHD patients, can actually exacerbate OCD behaviors, for example. Prescribed to an OCD patient, it will only worsen symptoms.

To determine the relationship between OCD and ADHD, the researchers studied three groups of subjects: 30 diagnosed with OCD, 30 diagnosed with ADHD, and 30 with no psychiatric diagnosis. All subjects were male with a mean age of 30. Comprehensive neuropsychological tests and questionnaires were used to study cognitive functions that control memory, attention, and problem-solving, as well as those that inhibit the arbitrary impulses that OCD and ADHD patients seem to have difficulty controlling.

As Dar and Abramovitch predicted, both the OCD and ADHD groups performed less than a comparison group in terms of memory, reaction time, attention and other cognitive tests. Both groups were also found to have abnormalities in their ability to inhibit or control impulses, but in very different ways. In real-world situations, the ADHD group had far more difficulty controlling their impulses, while the OCD group was better able to control these impulses than even the control group.

When people with OCD describe themselves as being impulsive, this is a subjective description and can mean that they haven't planned to the usual high degree, Dar explains .

It's understandable why OCD symptoms can be mistaken for ADHD. For example, says Dar, a student in a classroom could be inattentive and restless, and assumed to have ADHD. In reality, the student could be distracted by obsessive thoughts or acting out compulsive behaviors that look like fidgeting.

"It's more likely that a young student will be diagnosed with ADHD instead of OCD because teachers see so many people with attention problems and not many with OCD. If you don't look carefully enough, you could make a mistake," Dar cautions. Currently, 5.2 million children in the U.S. between the ages of 3 and 17 are diagnosed with ADHD, according to the Centers for Disease Control and Prevention, making it one of the most commonly diagnosed neuro-developmental disorders in children.

The correct diagnosis is crucial for the well-being and future trajectory of the patient, not just for the choice of medication, but also for psychological and behavioral treatment, and awareness and education for families and teachers.

STUDY HIGHLIGHTS:

"While frontostriatal deficiencies are implicated in both ADHD and OCD, the nature of the dysfunction is fundamentally different if not antithetical between the two disorders. Functional neuroimaging studies consistently report hypoactivity of the frontostriatal network in ADHD in comparison to control participants, and frontostriatal hyperactivity in OCD."

"This review of the literature appears to lead to a puzzling conclusion, namely that OCD and ADHD display similar executive function deficits but opposite underlying neurobiological processes of the frontostriatal system."

"In a review of the OC spectrum disorders across the lifespan, Hollander (2005) argued that impulsivity and compulsivity are phenomenologically different in that compulsive individuals are harm avoidant and risk aversive, whereas impulsive individuals underestimate harm and engage in risky behaviours. Hollander supports his view by pointing out that neurobiologically, impulsivity is associated with OFC underactivity, while in compulsivity, the OFC is hyperactive (Hollander, 2005)."

"Finally, our proposition regarding opposite mechanisms underlying similar neuropsychological impairments in ADHD and OCD, together with contrasting
clinical picture and pattern of brain activity, challenges the possibility of comorbidity
between the two disorders in the adult population."

ARTICLE:

"Comparative neuropsychology of adult obsessive-compulsive disorder and attention deficit/hyperactivity disorder: Implications for a novel executive overload model of OCD,." Abramovitch, A.; Dar, R.; Hermesh, H.; Schweiger. A. Journal of Neuropsychology, Volume 6, Issue 2. September, 2012. First published online December 2, 2011. DOI: 10.1111/j.1748-6653.2011.02021.x ©2011 The British Psychological Society.