Text adapted from "The patient with obsessive compulsive disorder" in Psychiatry in primary care by Peggy A. Richter and Steven Selchen (CAMH, 2019).
OCD shares some symptoms with other psychiatric disorders. The following section lists disorders that may be confused with OCD and describes how they differ.
Although patients with anxiety disorders may have recurrent thoughts or worries, these are typically about readily understandable, real-life concerns. For example, patients with generalized anxiety disorder may express excessive worries about losing their job or about the health and welfare of family members. Social phobia involves exaggerated but understandable concerns about embarrassing oneself in social interactions. By contrast, the obsessions experienced in OCD typically are very exaggerated or involve unrealistic or irrational concerns, and are usually accompanied by compulsions.
Major Depressive Disorder
The ruminations that people with depression experience typically are mood- congruent and generally are not experienced as intrusive.
Other Obsessive-Compulsive and Related Disorders
The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) features a category called “obsessive-compulsive and related disorders” (American Psychiatric Association, 2013). It includes the conditions listed here, each characterized by specific types of preoccupations and/or repetitive behaviours. It is important to differentiate between these related disorders because treatment approaches differ significantly for each one. Remember, however, that these disorders are often seen comorbidly:
- body dysmorphic disorder: excessive thoughts and repetitive behaviours related to perceived defects in one’s appearance (e.g., checking appearance in mirrors, seeking reassurance, spending a lot of time with grooming)
- hoarding disorder: difficulty discarding possessions, resulting in excessive accumulation of these items
- trichotillomania: repetitive hair-pulling, not accompanied by triggering obsessions
- excoriation disorder: repetitive skin-picking, not accompanied by triggering obsessions.
In eating disorders, preoccupations focus exclusively on food, weight or body image.
Illness anxiety disorder
Illness anxiety disorder features recurring thoughts that are exclusively related to fear of currently having a serious disease. In people with somatic obsessions, on the other hand, the concern is typically about contracting the illness in the future, and other obsessional content is present.
Tics are sudden, rapid, recurrent, non-rhythmic behaviours such as blinking, touching, grimacing or sniffing. They are not triggered by obsessions.
Although people with OCD may have poor insight or even be delusional about their obsessions, they do not have hallucinations or a formal thought disorder.
Obsessive-compulsive personality disorder
OCD and obsessive-compulsive personality disorder are not directly related. The personality disorder features a longstanding pattern of perfectionism and rigidity that the person perceives to be appropriate, rather than being intrusive the way obsessions are experienced in OCD. People with obsessive-compulsive personality disorder do not have true obsessions or compulsions.