Katharine Phillips, MD: Differences Between OCD, Body Dysmorphic Disorder

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In an interview, Phillip explained the difference between OCD and body dysmorphic disorder, even though they are grouped in the DSM-5.

OCD, body dysmorphic disorder, and trichotillomania may all be grouped into the obsessive-compulsive spectrum in the DSM-5—all sharing similarities of repetition—but their distinct differences make it crucial to treat each disorder on its own.1

Obsessive-compulsive disorders all share core obsessive-compulsive features. The spectrum stretches from compulsivity to impulsivity.

Many disorders can be confused with OCD. According to the International OCD Foundation, the DSM-5 grouped several disorders in the obsessive-compulsive spectrum due to common characteristics—OCD, hoarding disorder, body dysmorphic disorder, body-focused repetitive behaviors, olfactory reference syndrome, misophonia, and emetophobia.2 The disorders not grouped into the obsessive-compulsive spectrum but may be confused with OCD include tic disorders/Tourette syndrome, impulse control disorders, obsessive-compulsive personality disorder, autism spectrum disorders, and psychotic disorders/schizophrenia.

At the annual American Psychiatric Association (APA) conference in New York, Katharine Phillips, professor of psychiatry at Weill Cornell Medical College, presented the differences between obsessive-compulsive disorders, focusing on body dysmorphic disorder’s complex relationship with OCD and how their treatment regimen is similar yet different.1

OCD and body dysmorphic disorder are both defined by repetitive and obsessive thoughts. However, body dysmorphic disorder is appearance-focused.

“It’s about perceived flaws or defects in one’s personal appearance, so thinking ‘I look ugly, I don’t look right,” Katharine Phillips, MD, told HCPLive. “Some even think they look monstrous.”

The repetitive thoughts and behaviors of individuals with body dysmorphic disorder are different than those with OCD as they may have “compulsive mirror-checking or excessive grooming,” Phillips said.

In contrast, trichotillomania, a hair-pulling disorder, is a compulsive action without a triggering thought.

“[In body dysmorphic disorder], people can pull out their hair, but it’s because they think the hair looks ugly. It’s just an ugly hair or it's in response to thinking they have too much facial or body hair that they’re trying to get rid of or thinking their eyebrows are symmetrical,” Phillips said. “So, it’s actually pretty important to differentiate these.”

More research needs to be done to learn the mechanisms of these obsessive-compulsive disorders. Body dysmorphic disorder and OCD both share abnormalities—hyperactivity— in the corticostriatal circuit in the brain that may reflect the obsessions. The same abnormalities in the brain are not found for trichotillomania.

Twin studies found the disorders of body dysmorphia and OCD share the same genes. The disorders are genetically related, but they also have disorder-specific genes. For instance, body dysmorphic disorder shares some genes with OCD but trichotillomania has specific genes.

Phillips said people with body dysmorphic disorder have deviations in visual processing. The parts of the brain specialized to see detail are in overdrive, so tiny details in their appearance look very prominent to them.

“This may be why people with [body dysmorphic disorder] are usually certain or mostly certain that they really look abnormal or ugly because they’re actually seeing themselves in an abnormal way,” Phillips said.


  1. Phillips, K. Obsessive-Compulsive Spectrum Disorders: Clinical Presentations and Treatments. Session presented at: American Psychiatric Association (APA) 2024 Annual Meeting. New York, NY. May 4, 2024.
  2. Disorders Related to OCD. International OCD Foundation. Accessed May 10, 2024.