How Can OCD and ADHD Coexist?

Because obsessive-compulsive disorder (OCD) and attention-deficit/hyperactivity disorder (ADHD) are so different in theory, some doctors argue that they cannot occur together. However, they have a surprisingly high rate of comorbidity, which is when two medical conditions appear together, and many with ADHD report obsessive thoughts and behaviors. Continuing my series of posts about ADHD and comorbid conditions, I would like to discuss the similarities, differences, and possible treatments for OCD and ADHD.

What Symptoms Do OCD and ADHD Share?

Obsessive-compulsive disorder involves uncontrollable obsessive thoughts and/or compulsions that can create great anxiety. Sometimes OCD involves thinking repetitive thoughts or fearing that one’s thoughts and/or behavior will affect one’s environment, and psychologists now divide OCD into several categories depending on symptoms such as hair-pulling and hoarding.¹

In some cases, ADHDers exhibit OCD-like behavior to make up for their scattered focus. My world often feels out of control, so I make lists and double check things I could forget. To make up for my inability to sit still, I occasionally time myself before shifting positions. These acts might resemble OCD behavior, but they are not necessarily based on irrational fears and compulsions.

Other problems are harder to differentiate. Both ADHDers and those with OCD can struggle with hoarding. Both can be incredibly obsessive and perfectionistic. Sometimes I waste time trying to make a list exactly right, according to some arbitrary standard. I can completely lose track of time fiddling with my hair, which seems to be a compulsion I cannot control. It gives me temporary relief from anxiety, but the need to do it also causes stress and occasionally harms my head.

Why Are OCD and ADHD Sometimes Similar?

Family members with ADHD have reported similar behaviors. One plans to see a psychiatrist about a possible OCD diagnosis. Like ADHD, OCD appears to be genetic, so one has a high chance of sharing the conditions with a relative. Scientists debate how frequently the two conditions appear together. Some argue that they rarely overlap,² while others consider ADHD the most common additional diagnosis for those with OCD.¹

Both OCD and ADHD affect a part of the brain that controls executive function, which helps people organize information and regulate their brain and body. Interestingly, though this area of the brain seems to under-function in ADHDers and over-function in those with OCD, the results can look alike. For example, someone with ADHD might take a long time to perform a task because he keeps getting distracted, while a person with OCD may take her time because she is fixated on performing the task in a very specific way.

Also, both conditions impact important mood-affecting neurotransmitters. Attention-deficit/hyperactivity disorder correlates to a lack of dopamine, which stimulates the brain’s reward system, and OCD involves a deficiency of serotonin, which is tied to a number of functions including happiness. Both OCD and ADHD appear on a spectrum, and, even though they seem to be on the opposite ends of that spectrum, certain researchers find that there might not be such a thin line between the two conditions.³

ADHD and OCD Treatment

Sometimes people with OCD are misdiagnosed with ADHD and doctors advise those who might have both diagnoses to treat the OCD first. Stimulants used to treat ADHD often exacerbate OCD symptoms. Selective serotonin reuptake inhibitors (SSRIs) can treat both depression and OCD.

On a personal note, while on stimulants, I have noticed that my obsessive behavior remains about the same, but my thoughts related to that behavior become more irrational and obsessive. My relative with possible (but undiagnosed) OCD says that stimulants do not worsen his OCD symptoms.

Of course, therapy is recommended for those with ADHD and/or OCD. Ideally, find a therapist and psychiatrist who specialize in both. These conditions, especially when occurring together, can cause a lot of anxiety and stress.

In the video below, I address the theory that OCD and ADHD are too different to appear in one person.

Please let me know about your relationship with OCD and ADHD in the comments and if you believe they can occur together.

• Adult ADHD and Autism Link: Symptoms and Treatment,
• ADHD and Trauma Symptoms: How to Tell Them Apart and Treat Both,
• Why Do People with ADHD Have Problems Sleeping?
• ADHD and PMS Make Life Difficult

Sources

1. National Center for Biotechnology Information (NCBI). Sylvia Brem et. al. The neurobiological link between OCD and ADHD.
2. International OCD Foundation (IOCDF). Amitai Abramovitch and Andrew Mittelman. OCD and ADHD Dual Diagnosis Misdiagnosis and the Cognitive ‘Cost’ of Obsessions.
3. The Globe and Mail. Wendy Leung. ADHD, OCD, autism: Is it time to redraw the boundaries separating childhood behavioural disorders?