Around 1 in 10 individuals are estimated to have a ‘personality disorder’ (PD), which can lead to distressing patterns of behaviour. Research indicates that individuals with a diagnosis of PD represent about one-fifth of people exhibiting suicidal behaviours and are often involved in violent acts.
Antipsychotic medications, commonly prescribed to individuals with a PD diagnosis, have been shown to alleviate symptoms like false beliefs and hallucinations. The literature suggests that antipsychotics may reduce violent crime rates and positively impact the number of suicide attempts.
Given the high prescription rates of antipsychotics to individuals with a PD diagnosis, the study by Herttua et al. (2023) aimed to explore the benefits of these medications in managing PD-related risks.
Personality disorders affect approximately 1 in 10 individuals, often leading to severe behavioural patterns.
Methods
Researchers analysed Danish national registers data for individuals aged 18-64 from 2007 to 2016, identifying 166,328 with personality disorders. The researchers used antipsychotic treatment as the exposure and explored violent crime and suicidal behaviour as the outcomes. Antipsychotic treatment information was gathered by compiling data on all prescribed medications that individuals received and collected. Violent crimes were based on police reports (even those not pursued further), including all incidents. Similarly, both completed suicide and suicide attempts were identified using hospital records and death certificates.
The study compared outcomes between individuals on antipsychotics and those not, and investigated differences within the same individual when on and off antipsychotic medication.
Results
Overall, there was a potential association between the use of antipsychotic medication and decreased rates of violent crime suspicions and suicidal behaviour among individuals with diagnosed PDs.
48% of individuals with diagnosed PDs (79,253 patients) received antipsychotic prescriptions. Those on antipsychotics were more likely to use other mental health drugs. Demographically, those prescribed antipsychotics were mostly men, less educated, and living alone. The main personality disorder subcategories were emotionally unstable, unspecified, anxious (avoidant), and mixed/other.
Relationship with violent crime and suicidal behaviour
- Men receiving antipsychotics were nearly twice as likely to be suspected of committing violent crimes and 29% more likely to show signs of suicidal behaviour.
- Women on antipsychotics had an even greater risk, being over three times more likely to be suspected of violent crimes and 55% more likely to display suicidal behaviour.
- During antipsychotic use: both men and women had significantly lower rates of suspicions for violent crime and suicidal behaviour.
- The likelihood of suicidal attempts was reduced by 32% for both men and women.
- The same effect was found when adjusting for age and concomitant use of antidepressants and hypnotics/anxiolytics.
- For individuals who were prescribed both antipsychotics and lithium, a comparable pattern of association was identified, though with less pronounced effects in men.
Specific diagnoses of personality disorders
- Antipsychotic use and violence: Reduced suspicions of violent crimes across various personality disorders, especially in dissocial personality disorder (reduced by 0.53 times).
- Antipsychotic use and suicidal behaviour: A notable decrease in suicidal behaviour was observed across all personality disorder subcategories.
Reliability analyses
Examining the impact of adrenergic inhalers (a medication to help breathing with minimal mood effects) revealed no negative outcomes; and excluding events occurring 7 to 30 days before medication periods didn’t change the observed associations.
When on antipsychotics, both men and women diagnosed with personality disorders showed significant reductions in violent crime suspicions and suicidal behaviour.
Conclusions
The authors found that individuals with personality disorders prescribed antipsychotic medications had reduced reports of violent crime suspicions and suicidal behaviour compared to periods without antipsychotics. The associations between antipsychotics and suicidal behaviour were homogenous across four common personality disorders (emotionally unstable, unspecified, anxious-avoidant and mixed). However, antipsychotics had a stronger impact on violent crime suspicions in dissocial and emotionally unstable types (cluster B disorders), possibly due to impulsivity and emotional dysregulation symptoms.
This suggests possible short-term benefits from antipsychotic medication in preventing violent crimes and suicidal behaviour in individuals with personality disorders.
Antipsychotics showed stronger efficacy in reducing violent crime suspicions among dissocial and emotionally unstable personality disorder diagnoses.
Strengths and limitations
The study has a few methodological strengths:
- Big cohort data: The study benefits from extensive data from a large cohort, enhancing the depth of analysis.
- Within comparison group: By comparing individuals with schizophrenia who were exposed to antipsychotic medication to those who were not within the same cohort, the study methodology minimises certain biases and confounding variables. This enhances the validity of the findings.
However, we should also acknowledge certain limitations:
- The study is not clear about what constitutes a violent crime or suicidal behaviour: This means it could be difficult to categorise. Another explanation for the results could be that people who are more likely to engage in risky behaviours might be more likely to be prescribed antipsychotic medication.
- No actual evidence of whether the medication was taken by participants: Given the common occurrence of non-adherence among psychiatric patients, this gap could significantly skew the results, potentially leading to inaccurate conclusions.
- No evidence for practice: Without insights into the actual clinical protocols governing the administration of antipsychotic medication, it is challenging to understand the contextual factors influencing prescription patterns and their potential impact on the studied outcomes.
- No information on dosage of antipsychotics prescribed: Since dosage variations can influence both efficacy and side effects, the absence of this information makes it difficult to assess the full impact of medication use.
- Limited generalisability: May not be applicable for the general population outside Denmark. Differences in healthcare systems, cultural factors, and demographic characteristics could all influence the effectiveness and outcomes of antipsychotic medication use in other populations.
The use of clearly defined terms, such as suicidal behaviour, could increase the validity of the findings.
Implications for practice
The authors suggest clinicians should consider this study’s findings when identifying treatment options for people diagnosed with personality disorders. Clinicians may lower their threshold for prescribing antipsychotic medications to people diagnosed with personality disorders if they think it may reduce their risk of violent or suicidal behaviour. This could have both individual and wider social benefits if the reported effect is genuine.
However, these medications carry significant side effects and may, therefore, also bring about harm to those taking them. Such side effects are already well described in the literature.
The authors suggest possible explanations for the observed effect, including factors related to the medications themselves (like propensity to reduce impulsivity and emotional lability) and non-specific factors (like instillation of hope and increased clinical contact that typically comes with antipsychotic prescription), but no conclusions on this can be drawn from the data they had available to them.
Based on the evidence presented, formal changes to clinical guidance on personality disorder treatment are, in our opinion, not justified. However, it would be reasonable to explore the reported effect further.
We would therefore suggest further research to understand better:
- Whether the observed effect could be explained by something else (for example, having other mental health difficulties alongside the diagnosis of ‘personality disorder’ or struggling with substance misuse).
- If the observed reduction in suicidal and violent behaviour is caused by antipsychotic prescription, is this related to the drug itself or something else? For example, would an increased contact with mental health services and appropriate psychiatric reviews and medication monitoring have a similar impact?
- Do the potential benefits of antipsychotics in this scenario outweigh the potential harms associated with their prescription which are extensive and well-documented?
- Taking into consideration the social justice movement on ‘personality disorders’ and the better understanding of complex PTSD, would psychological interventions to learn skills in managing emotional dysregulation and impulsivity symptoms be more effective to prevent suicidal behaviour and violent crimes compared to psychiatric medication in this population?
Is this evidence for clinicians to consider lowering their threshold for prescribing antipsychotic medications to individuals with a diagnosis of personality disorders?
Statement of interests
No conflicts of interest to declare.
Contributors
Thanks to the UCL Mental Health MSc students who wrote this blog from Drini B student group: Adam Clare, Alexis Gott, Kelechi Matthias, Amy Robinson, Emanuelle Rossetti, and Matt Young.
UCL MSc in Mental Health Studies
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