epearls newsletter, April 2009:

I was struck not long ago by the clinical similarities between obsessive-compulsive disorder and schizophrenia (referred to in the literature as so-called schizophrenia spectrum disorders, or SSD’s), so much so that I went to the literature to learn more about their relationship.  I hereby present to you the results of my brief investigation.

Background

Let me start off by saying that the clinical significance of the association between obsessive-compulsive disorder and obsessive-compulsive symptoms (OCD and OCS, respectively) and schizophrenia is not without controversy.  Hold that thought for now; I’ll get to it a bit later. 

It has been known for over a century that such an association exists; for instance, in 1878 Westphal postulated that OCD was a variant or prodrome of schizophrenia.  Although the literature does not seem to support such a direct relationship, there is evidence that individuals with anxiety disorders in general (e.g., OCD, panic disorder, social phobia) have an increased risk of developing schizophrenia.  This varies according to the study cited, but long-term follow-up studies of patients with OCD often show incidence rates of SSD’s to be in the 5-12% range.  This is much higher than the average incidence of schizophrenia worldwide of approximately 0.5%-1%. 

In fact, some modern authors have postulated that OCD and schizophrenia represent a psychopathological spectrum, determined by the degree of insight that is present.  The thinking here is that patients at the more severe end (SSD) possess little or no insight; the clinical shift from obsessions to delusions may take place when insight is lost. 

In addition, it is not hard to imagine that some compulsive behaviors, along with the stated reasons for them, might seem bizarre even to a sophisticated observer, resulting in a mistaken diagnosis of schizophrenia.  This is obviously of great importance, since the treatment of schizophrenia is quite different from that of OCD, to say nothing of the emotional consequences both to the affected individual and his or her family of such a mistaken diagnosis.

OCD and Schizophrenia: Significant Comorbidity

As alluded to above, it has been known for some time that there seems to be some association between OCD and SSD’s.  Whether this actually represents a clinical spectrum is still controversial, but the fact that OCD and/or OCS co-exist with schizophrenia in a significant number of patients is well-established.

There is some variation in OCD prevalence reported in the literature between those patients with recent-onset as opposed to chronic schizophrenia.  For the former, the prevalence of OCD ranges between 3.5% to 47.6%, with most reports ranging somewhere between 11 and 15%.  In the latter, more chronic patients, the prevalence of OCD is somewhat higher, ranging between 18% and 37.5%, with most studies reporting a prevalence of between 22% and 30%.  The average rate may be somewhat higher during the prodrome of childhood schizophrenia (41%) and in adolescents with SSD’s (26%).  This variability may in part be accounted for by different reporting techniques (self-rating scales vs. structured clinical interviews, for example) as well as by demographic variations in the respective study populations.      

Based on their significant comorbidity, some authors even have gone so far as to advocate for the establishment of a new diagnostic sub-category of schizophrenia, a so-called “obsessive-compulsive” type.

Okay, so OCD/OCS and SSD’s are often co-morbid.  What does that mean clinically?  Indeed, there appears to be considerable variation in the literature on this very point.  Some authors have reported that the presence of OCD/OCS in schizophrenia predicts a more favorable outlook, with greater insight and fewer negative symptoms.  Others report exactly the opposite: a greater incidence of negative symptoms and a worse clinical course both in terms of treatment response and impairment of functioning.  In other words, the clinical significance of OCD or OCS in schizophrenia remains uncertain.

Concluding Thoughts

This discussion is certainly not, and is by no means intended to be, an exhaustive review of the subject.  However, the literature does seem to justify several conclusions:

1) OCD appears to occur in patients with schizophrenia/SSD’s at a higher rate than in the general population.

2) Comorbid anxiety disorders, such as OCD, may precede the onset of SSD’s in some patients.

3) The presence of OCD may offer some insight into the course of schizophrenia, although the literature is quite variable on this point.

4) The relationship between OCD and schizophrenia/SSD’s merits further investigation.

References

Hwang, M. Y., & Losonczy, M. F. (1997). Schizophrenia with obsessive-compulsive features. Medscape Psychiatry and Mental Health eJournal, 2,4 . Retrieved April 1, 2009, from Medscape database.

Kayahan, B., Ozturk, O., Veznedaroglu, B., & Eraslan, D. (2005). Obsessive-compulsive disorder in schizophrenia: Prevalence and clinical correlates. Psychiatry and Clinical Neurosciences, 59, 291-295.

Pokos, V., & Castle, D. (2006). Prevalence of comorbid anxiety disorders in schizophrenia spectrum disorders: A literature review. Current Psychiatry Reviews, 2, 285-307.

Reznik, I., Mester, R., Kotler, M., & Weizman, A. (Winter 2001). Obsessive-compulsive schizophrenia: A new diagnostic entity? [Letter to the editor]. Journal of Neuropsychiatry and Clinical Neuroscience, 13, 115-116.

Rodowski, M. F., Cagande, C. C., & Riddle, M. A. (2008). Childhood obsessive-compulsive disorder presenting as schizophrenia spectrum disorders. Journal of Child and Adolescent Psychopharmacology, 18, 395-401.