Comorbidity of mental disorders and substance use: a brief guide for the primary care clinician
8.5 Major clinical issues with personality disorders and opioid use
- A significant number of people with opioid dependence also have personality disorders.
- Particularly in the opioid dependent population, it is important to try to determine whether the behaviours are due to the opioid dependence or due to antisocial personality disorder.
- The presence of a personality disorder does not appear to impact on the effectiveness of opioid treatment.
- Methadone maintenance appears to be effective in people with personality disorders.
- Carbamazepine is a potent CYP inducer and will induce the metabolism of methadone and buprenorphine.
- Opioids can increase the sedative effects of carbamazepine, lithium and sodium valproate.
8.5.1 Effects of opioids on personality disorders
- A significant number of people with opioid dependence also have personality disorders(312, 333). Particularly in the opioid dependent population, it is important to try to determine whether the behaviours are due to the opioid dependence or the antisocial personality disorder.
- Opioid dependent people with personality disorders have more severe substance dependence as well as polydrug dependencies(312).
- Individuals with comorbid personality disorders and opioid dependence(312, 333):
- Participate in more criminal activities (likely related to procurement of drugs).
- Participate in more risky injecting behaviour.
- Have higher rates of suicidality and overdose.
- Have more psychological distress compared to opioid dependent individuals without personality disorders.
- The presence of a personality disorder does not appear to impact on the effectiveness of opioid treatment; however, it may affect retention and result in continual switching between treatment regimes(312, 334):
- Treatment reduces participation in crime and improves injecting behaviour as well as risk of overdose and psychological distress. However, rates still remain above those without personality disorders(334).
- Treatment improves risk of suicide to a level that is comparable to those without personality disorders(334).
- As with others who have initial legitimate needs for opioids to control pain, people with personality disorders may go on to develop dependence to opioids and feel a need to increase their dosage. This may be a contributor to the above-mentioned switching of treatment regimes or treatment providers in order to obtain subsequent increases in opioid dose.
8.5.2 Interactions between opioids and therapeutic agents for personality disorders
- Opioids can increase the sedative effects of carbamazepine, lithium and sodium valproatex.
- Carbamazepine is a potent CYP inducer and will induce the metabolism of methadone and buprenorphine as well as reduce plasma concentrationsxx(149, 157). This has the potential to result in withdrawal and failure of retention in treatment****(158-160).
- Opioids can exacerbate the sedative effects as well as increase the risk of overdose with tricyclic antidepressantsxx(161).
8.5.3 Management approaches to comorbid personality disorders and opioid use
- Methadone maintenance appears to be effective in people with personality disorders**(335, 336).
- Close liaison between the prescribing clinician and the pharmacist dispensing the opioid maintenance will assist with gaining insight into adherence to treatment, levels of self care and general stability.
- Considering the potential of personality disorders to impact on treatment retention, oral naltrexone is less likely to be effective in individuals with personality disorder.