The Role of Antipsychotics in OCD

Successful treatment of obsessive-compulsive disorder (OCD) often requires primary psychotherapeutic treatment with exposure and response prevention (ERP) and pharmacological treatment with serotonergic agents, usually beginning with SSRIs; However, for a subset of patients with OCD, SSRIs alone do not effectively control symptoms. There are a number of augmentation strategies to consider in these cases. This blog post will focus on the strategy of adding an antipsychotic medication to an SSRI.

Some patients may be uncomfortable with the idea of ​​starting an antipsychotic, in part because the term “antipsychotic” is a misnomer that could imply an element of its presentation that is not entirely accurate. To this end, it may be helpful to educate about the fact that antipsychotics can be effective for conditions other than psychosis, in the same way that antidepressants can be effective for conditions other than depression.

While guidance on augmenting an SSRI with an antipsychotic is somewhat limited due to a small number of trials, the following guidelines are fairly consistent across available studies and meta-analyses:

• ERP is superior to risperidone in reducing OCD symptoms. That is, if a patient is not already participating in high-quality ERP and does not respond adequately to treatment with an SSRI, encouraging ERP is likely to be more effective and carry a less negative risk profile than starting an antipsychotic. According to one study, more than half (56 percent) of patients who did not respond to placebo or risperidone were found to have a treatment response with a course of 17 sessions of ERP (McLean).
• If a patient has a partial response to an SSRI, the best next step is probably to adjust the SSRI dose, as OCD often requires higher doses of SSRIs to achieve full effect; However, if there is no response to an SSRI, the best next step may be to add an antipsychotic.
• Consider starting an antipsychotic for augmentation after at least twelve weeks of an adequate trial with SSRIs. Studies suggest that one in three patients who do not respond to SSRIs improve with increasing antipsychotics, and an appropriate trial duration of an SSRI for OCD is at least twelve weeks.
• Greater symptom severity correlates with a lower response to antipsychotics. Available studies have shown that antipsychotics are less effective in more severe cases of OCD than in moderate cases. In other words, perhaps counterintuitively, it is not advisable to reserve antipsychotic escalation for patients with the most severe OCD symptoms.
• In terms of selection, the most evidence-based options are aripiprazole and risperidone. Haloperidol may also be considered, although it has a side effect profile that is generally less tolerable than second-generation options. Furthermore, olanzapine and quetiapine have not been differentiated from placebo and are not considered first-line for this purpose. Other drugs in this class have not been adequately evaluated.
• Use relatively low doses of antipsychotics to minimize side effects and consider the side effect profile when deciding between medications. In general, aripiprazole tends to be better tolerated than risperidone.
• As for dosing, low to moderate doses are typically recommended to maintain tolerability, although if a patient has a partial response and tolerates the medication well, further titration may be considered. Here are conservative recommendations for dosage ranges:
  • Aripiprazole: 5-10 mg
  • Risperidone: 1-3 mg
  • Haloperidol: 2.5-10 mg
• There is an increased risk of QTc prolongation when second-generation antipsychotics are combined with clomipramine. Use caution and proper control when using this combination.
• Studies show some variability regarding the required trial duration. Generally, there is likely to be some effect to measure within four weeks. If there is no response to the increase within four weeks, the recommendation is to discontinue the antipsychotic.
• After achieving remission of symptoms with an antipsychotic, this medication should be continued for at least one year. Studies have shown relapse when antipsychotics are stopped prematurely (for example, after three months).
• When prescribing antipsychotics for any purpose, it is important to follow guidelines for routine monitoring of weight, fasting plasma glucose, A1c, lipids, and blood pressure.

In summary, augmenting an SSRI with an antipsychotic medication may be an effective strategy that can generate a treatment response in approximately one-third of patients who have not responded to an SSRI alone. Based on current evidence, we strongly recommend a low to moderate dose of aripiprazole, risperidone or haloperidol as specific agents for this purpose. Once a patient achieves a favorable effect with one of these medications, we recommend continuing the medication for at least a year to avoid early relapse. Greater monitoring is necessary when prescribing antipsychotics versus SSRIs or clomipramine alone.

Given that medication management alone is often insufficient to treat OCD and that a good number of patients discontinue effective medication due to adverse effects, we must also highlight the role of psychotherapy. A high-quality ERP remains one of the main recommendations for patients with OCD. ERP has been shown to be more effective than augmentation with an antipsychotic and should be the primary recommendation for patients who have not responded to a serotonergic agent alone.

This publication is brought to you in collaboration with the ADAA OCD and Related Disorders SIG.More information about GIS.

References

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