Schizophrenia and OCD: A Consideration of Schizo-Obsessive Disorder

by Robert Hudak, MD

This article was initially published in the Spring 2018 edition of the OCD Newsletter

Schizophrenia is a severe and chronic mental illness that affects approximately one percent of the population. It is a psychiatric disorder with the potential to significantly impact a person’s social and occupational functioning. Complicating things further, some individuals with schizophrenia experience co-occurring obsessive compulsive disorder, which makes diagnosis and treatment even more challenging. In fact, there is a large enough group of individuals experiencing both disorders that some have proposed the idea of a “schizo-obsessive disorder.” A proper diagnosis leads to effective treatment; therefore, it is critical that the mental health provider conduct a comprehensive and thorough assessment and ask the right questions in order to determine the correct diagnosis. An additional obstacle in working with individuals with co-occurring schizophrenia and OCD is that there has been little research into effective treatments for this group. However, what we know about treating OCD should help inform treatment approaches for those with co-occurring schizophrenia and OCD.

Schizophrenia and OCD Overlap

Schizophrenia and obsessive compulsive disorder (OCD) share some important traits:

  • Both are severe and chronic mental illnesses;
  • Both disorders are linked to abnormalities in brain structure and functioning;
  • Both can contribute to difficulties in employment, interpersonal relationships, and emotional and mental well-being.

Of note, while people with OCD do not appear any more likely than the general population to have schizophrenia, people with schizophrenia experience obsessive compulsive (OC) symptoms at an increased rate. While the rate of OCD in the general population is approximately 1%, the rate of OC symptoms in people with schizophrenia is 25%, and the percentage of people with full-blown OCD is 12% (Scotti-Muzzi and Saide 2017). It has also been noted that in many people who later develop schizophrenia, their first clinical symptoms are often an OCD-like presentation, and the schizophrenia diagnosis becomes clearer over time. Because of the common co-occurrence between the two disorders, a proposed diagnostic term of “schizo-obsessive disorder” has been discussed extensively in scientific literature.  While not yet an official psychiatric term in the Diagnostic and Statistical Manual of Mental Disorders (DSM), this potential diagnosis has begun to receive some study and attention.

Issues Around Diagnosis

Schizophrenia is identified by the presence of delusions, hallucinations, or disorganized speech as well as disorganized behavior or “negative symptoms.” Let’s take a moment to define some of these terms:

  • A hallucination is defined as a false sensory perception. For example, hearing a voice speaking to you when in fact no one is present.
  • Delusions are defined as unfounded, idiosyncratic beliefs that are held without supporting evidence. For example, a typical delusion in schizophrenia sufferers is that aliens have implanted a chip in their brain and are using it to control them. No amount of evidence (such as offering to do an MRI of their brain) will convince them otherwise.
  • Examples of “negative symptoms” of schizophrenia include reduced emotional expression and extreme difficulty making decisions.

One of the trickier parts of determining whether someone is struggling with schizophrenia versus OCD is trying to understand if the individual is experiencing a delusion or an obsession. The rule of thumb is that delusions are consistent with a person’s ideas about themselves, including their needs and their ideal self-image. People suffering from delusions are comfortable and accepting of their beliefs and see no need to question the presence of such a belief nor the content of it. The technical term for this is “ego-syntonic” (i.e., this is in sync with my sense of self).

In contrast, obsessions are inconsistent with one’s needs and self-image. People with OCD usually have doubts that the content of their obsession is true, and they will usually question why they are having an obsessive thought in the first place. The mere presence of the thought makes them uncomfortable. In this case, we call these thoughts “ego-dystonic” (i.e., this doesn’t feel like me).

Unfortunately, while these definitions sound very different, in clinical practice they can be difficult to distinguish. Additionally, many patients have both ego-syntonic and ego-dystonic thoughts. As previously mentioned, because of the increased likelihood of schizophrenia and OCD occurring together, as well as this complicated relationship between obsessions and delusions, a new diagnostic category of “schizo-obsessive disorder” was proposed in the 1990s. To qualify for this diagnosis, the patient must have symptoms of both disorders. Schizo-obsessive disorder is currently being conceptualized as a subtype of schizophrenia rather than a subtype of OCD. Diagnostic criteria for this disorder have been proposed by Poyurovsky et al. (2012) and include:

  • Symptoms that meet criteria for OCD must be present at some point in someone who has a diagnosis of schizophrenia;
  • If the content of the obsessions and/or compulsions is interrelated with the content of delusions and/or hallucinations (e.g., compulsive hand washing due to command auditory hallucinations), additional typical OCD obsessions and compulsions recognized by the person as unreasonable and excessive are required;
  • OCD symptoms are present for a substantial period of the schizophrenia diagnosis;
  • The OCD must cause significant distress or dysfunction that is separate from the impairment associated with schizophrenia; and
  • OCD symptoms cannot be caused by antipsychotic agents, substances of abuse, or other medical issues.

According to these criteria, a person is not considered to have schizo-obsessive disorder if OC symptoms occur solely in the context of a delusion.

  • For example, if someone heard voices telling them their hands were contaminated, and as a result they repeatedly washed their hands, this would not be considered schizo-obsessive disorder. In such patients, the handwashing would be expected to improve after treatment for the auditory hallucinations.

Often, a patient will have both delusions and obsessions about the same themes.

  • For example, a patient with schizo-obsessive disorder may have the delusion that they are the devil when they are psychotic. After their psychosis is treated, they may have scrupulosity or religious obsessions that they are evil or are going to hell, and will have rituals centered on those thoughts (e.g. compulsive praying, or compulsive checking if they have a tail like a devil might). If the recurrent intrusive thoughts occur solely about the themes of the patient’s delusions, this is not considered schizo-obsessive disorder (Bottas et al 2005).

In this example, to qualify as having schizo-obsessive disorder, such an individual would need to have other, separate obsessions and compulsions. OCD symptoms that occur in patients with schizophrenia do not present differently than in people with OCD alone; they present the same in both groups of patients.

Proposed Treatment Approaches for Individuals with Schizo-obsessive Disorder

There have been few studies focused on the treatment of people with schizo-obsessive disorder. As a result, little is known about the effects of Exposure with Response Prevention (ERP) in this group. That said, there is a good argument that ERP should still be considered the first treatment to try. In my clinical experience, patients with decreased insight into their obsessions (i.e., obsessions that are more ego-syntonic) will often respond just as well to ERP as patients with better insight (i.e., when their obsessions are ego-dystonic). The real challenge, in fact, is getting them to agree to participate in ERP treatment!

Another treatment approach would be to use medication. Unfortunately, OCD symptoms rarely respond to antipsychotic medications. To start, anti-psychotic medications can be used to treat the schizophrenia symptoms, and treatment for obsessions would be initiated after sufficient resolution of psychotic symptoms has occurred. The good news is that the same medication protocols used to treat individuals with OCD work the same way in individuals with schizo-obsessive disorder (Borue et al 2015). Certain anti-psychotic medications, such as clozapine, are believed (although not proven) to induce obsessions in patients or worsen already existing obsessions. Therefore, if possible, it is best to avoid this medication in someone who is schizo-obsessive.


To improve clinical outcomes in people with OCD as well as people with schizo-obsessive disorder, additional research is needed on the relationship between obsessions and delusions, as well as thoughts that may fall somewhere between obsessions and delusions (termed “overvalued ideas” in the literature). Also, increased cooperation in academic settings between schizophrenia researchers and OCD researchers, clinicians, and therapists should occur. Finally, similar to issues that arise for co-occurring OCD and substance use disorders, schizophrenia and OCD programs should develop bridge programs to help educate people with schizophrenia and schizo-obsessive-like presentations and prepare them for exposure with response prevention treatment in OCD programs.

Recommended reading

Schizo-obsessive Disorder. Michael Poyurovsky. Cambridge University Press. 2013

Schizo-obsessive spectrum disorders: an update. Scotti-Muzzi E, Saide OL. CNS Spectrums (2017) 22, 258-72

Diagnostic and Statistical Manuel of Mental Disorders 5. American Psychiatric Association

Obsessions, Overvalued ideas, and Delusions in Obsessive Compulsive Disorder. Kozak MJ, Foa EB. Behav Res Ther 1994 March; 32(3):343-53

Comorbidity and pathophysiology of obsessive-compulsive disorder in schizophrenia: is there evidence for a schizo-obsessive subtype of schizophrenia? Bottas A, Cook RG, Richter MA. J Psychiatry Neurosci 2005 May; 30(3): 187-93

Obsessive-compulsive symptoms in schizophrenia: implications for future psychiatric classifications. Poyurovsky M, Zohar J, Glick I et al. Comprehensive Psychiatry 53 (2012). 480-83

Biological Treatments for Obsessive Compulsive and Related Disorders. Borue X, Sharma M, Hudak R. Journal of Obsessive Compulsive Related Disorders. July 2015 (16): 7-26