Diagnosis and Management of Obsessive Compulsive Symptoms (OCS) in Schizophrenia

There are phenomenological differences between OCS and delusions which assists in the differentiation of psychosis from OCD, however in some cases this boundary may blur and may result in a misdiagnosis. [Rodriguez et al., 2010], [Oulis et al., 2013]

The onset of OCS can occur at different stages of the illness: [Zink, 2014]

1. Before psychosis as an independent, coexisting syndrome and diagnosed as OCD
2. Prior to psychotic manifestation as part of the at-risk mental state (ARMS)
3. In parallel to the first manifestation of psychosis
4. During the course of chronic schizophrenia
5. As exacerbated or second-onset (de novo) OCS after initiation of antipsychotic treatment.

Differentials in patients presenting with both psychotic and OC symptoms include:

• Comorbid schizophrenia and obsessive-compulsive disorder / Schizo-obsessive disorder [Scotti-Muzzi & Saide, 2017]
• OCD with poor insight
• Schizophrenia with antipsychotic-induced obsessive-compulsive symptoms.

It has been demonstrated that patients with schizophrenia and comorbid OCD have a more severe illness, and the presence of the latter is associated with more severe depression, more impaired social functioning, and also worse premorbid functioning. [de Haan et al., 2013]

A meta-analysis of 148 patients with comorbid schizophrenia and obsessive-compulsive disorder showed that  48% developed OCS and were diagnosed with obsessive-compulsive disorder(OCD) first, 30.4% developed schizophrenia first, and 21.6% were diagnosed with both concurrently. [Devulapalli et al., 2008]

OCS is considered in some cases to be a prodromal stage of schizophrenia due to the temporal occurrence of OCS before schizophrenia.

Atypical antipsychotic treatment of schizophrenia (particularly clozapine, but also olanzapine and risperidone) can precipitate OC symptoms in specific individuals.

Some 2^nd generation antipsychotics (SGA’s) have a predominantly anti-serotonergic profile with both 5-HT2A and 5-HT2C receptor antagonism, which may precipitate OC symptoms in individuals.

Glutamate is also implicated in the causation of OCD and schizophrenia, and many 2^nd-generation antipsychotics also act on the glutamate system. Several studies investigated glutamate in OCD using neuroimaging and found that various areas of the brain in people with OCD appear to be abnormal. (More on the neurobiology of OCD)

One study of 21 unmedicated OCD patients found that CSF glutamate levels were significantly higher in patients with OCD, and these levels were unaffected by gender, age, duration of illness, Y-BOCS score or CGI-S score. [Chakrabarty et al., 2005]

Both schizophrenia and OCD involve the prefrontal cortex and striatal areas and this may explain the co-occurence.

There are no clear guidelines for the treatment of OCS in schizophrenia due to the limited evidence base.

The following algorithm has been developed based on the articles by:

[Zink 2014], [Poyurovsky et al., 2004] & [Rosli & Ismail, 2015]  and the talk by Dr Lynne Drummond at the RCPsychIC 2019.

Practical considerations:

There is evidence to suggest that reducing or stopping clozapine can reduce OC symptoms in around 50% of affected patients, but this may be difficult if clozapine is working for an individual.[Grover et al., 2015]

Addition of an SSRI can be useful although clomipramine can worsen psychosis and SSRI/clomipramine has also been shown to increase the risk of seizures by altering blood levels of clozapine.

Pharmacokinetic interactions with fluvoxamine can increase blood levels of clozapine (Fluvoxamine is a CYP1A2 inhibitor). For further information regarding pharmacokinetics and mechanisms of antidepressants and antipsychotics. 

CBT is safe and does not worsen psychotic symptoms. CBT is effective, with a symptom reduction quite similar to that reported for patients with OCD without psychosis and for SSRI treatment of OCD co-occurring with psychosis.

It is also effective in patients with OCD induced by second-generation antipsychotic as well as in patients with OCD not induced by second-generation antipsychotic. [Tundo et al.,2016]