A clinical approach to pharmacotherapy for personality disorders

Targeting comorbid disorders. National Institute for Health and Care Excellence guidelines for antisocial and borderline PD recommend that clinicians focus on treating comorbid disorders, a position echoed in Cochrane and other reviews.^4,9,22-26 For example, a patient with borderline PD experiencing a major depressive episode could be treated with an antidepressant. Targeting the depressive symptoms could boost the patient’s mood, perhaps lessening the individual’s PD symptoms or reducing their severity.

Targeting important symptom dimensions. For patients with borderline PD, several guidelines and reviews have suggested that treatment should focus on emotional dysregulation and impulsive aggression (mood stabilizers, antipsychotics), or cognitive-perceptual symptoms (antipsychotics).^4-6,15 There is some evidence that mood stabilizers or second-generation antipsychotics could help reduce impulsive aggression in patients with antisocial PD.²⁷

Choosing medication based on similarity to another disorder known to respond to medication. Avoidant PD overlaps with social anxiety disorder and can be conceptualized as a chronic, pervasive social phobia. Avoidant PD might respond to a medication known to be effective for treating social anxiety disorder, such as a selective serotonin reuptake inhibitor (SSRI) or venlafaxine.²⁸ Treating obsessive-compulsive PD with an SSRI is another example of this strategy, as 1 small study of fluvoxamine suggests.²⁹ Obsessive-compulsive PD is common in persons with obsessive-compulsive disorder, and overlap includes preoccupation with orders, rules, and lists, and an inability to throw things out.

Targeting the PD syndrome. Another strategy is to target the PD itself. Clinical trial data suggest the antipsychotic risperidone can reduce the symptoms of schizotypal PD.³⁰ Considering that this PD has a genetic association with schizophrenia, it is not surprising that the patient’s ideas of reference, odd communication, or transient paranoia might respond to an antipsychotic. Data from randomized controlled trials (RCTs) support the use of the second-generation antipsychotics aripiprazole and quetiapine to treat BPD.^31,32 While older guidelines^4,5 supported the use of the mood stabilizer lamotrigine, a recent RCT found that it was no more effective than placebo for borderline PD or its symptom dimensions.³³

What to do before prescribing

Before writing a prescription, the clinician and patient should discuss the presence of a PD and the desirability of treatment. The patient should understand the limited evidence base and know that medication prescribed for a PD is off-label. The clinician should discuss medication selection and its rationale, and whether the medication is targeting a comorbid disorder, symptom dimension(s), or the PD itself. Additional considerations for prescribing for patients with PDs are listed in Table 3.³⁴

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