Treatment of Hypochondriasis in Two Schizophrenia Patients Using Clozapine

Relationship between clozapine dose and severity of obsessive-compulsive symptoms

Evidence supports the fact that clozapine can induce stressful obsessive-compulsive symptoms (OCS). Although clozapine's robust inhibition of serotonergic neurotransmission is believed to be a key mechanism underlying clozapine-induced OCS, the exact mechanism(s) are not fully understood. Intuitively, it is reasonable to believe that the dose of clozapine is likely related to emergent OCS severity. However, there is conflicting evidence where both positive and inverse relationships have been demonstrated between clozapine dose and emergent OCS severity. Upon examination of clozapine's receptor profile, in particular its affinity for 5-HT_2A and D₂ receptors, we hypothesize that there is a biphasic relationship between clozapine dose and emergent OCS severity. We present here a preliminary analysis of published cases in the literature to support our hypothesis.

Clozapine-Associated Obsessive-Compulsive Symptoms and Their Management: A Systematic Review and Analysis of 107 Reported Cases

BACKGROUND

It is not uncommon to find obsessive-compulsive symptoms (OCS) in patients treated with clozapine. These symptoms are attributed to anti-serotonergic effects of clozapine. The objective of this study was to conduct a systematic review of reported cases of clozapine-associated OCS to better understand the nature and management of these symptoms.

METHODS

MEDLINE, Embase, and PsycINFO databases were searched with no publication year or language restrictions. Studies reporting cases of clozapine-associated OCS, either de novo or exacerbation of preexisting OCS, were included. The final search date was July 11, 2019.

RESULTS

Fifty-seven studies, involving 107 cases (75 de novo, 32 exacerbated OCS), were included. Clozapine triggered moderate-severe OCS at varying doses (100-900 mg/day) and treatment durations (median 6 months, interquartile range 2-24 months). Higher severity was significantly associated with preexisting OCS, poorer insight into OCS, and active psychosis at the time of OCS. Common strategies to treat clozapine-associated OCS included adding selective serotonin reuptake inhibitors, clomipramine, or aripiprazole, often accompanied by clozapine dose reduction. The rate of response to antidepressants was 49% (29/59), where younger age, shorter duration of underlying illness, shorter cloza-pine treatment duration, better insight into OCS, and presence of taboo thoughts were significantly associated with antidepressant response. Subsequent clozapine dose reduction was effective in many non-responders, where aripiprazole was simultaneously added in 50% (8/16).

CONCLUSIONS

Clozapine can trigger severe OCS. Adding aripiprazole with/without clozapine dose reduction may be a good alternative to antidepressants for managing clozapine-associated OCS. Clinicians should be more vigilant about these adverse effects and administer appropriate treatments.