Access to means of lethal overdose among psychiatric patients with co-morbid physical health problems: Analysis of national suicide case series data from the United Kingdom.

BACKGROUND

Many physical health problems are associated with elevated suicide risk whilst also providing access to means of overdose. We aimed to investigate whether psychiatric patients with physical co-morbidities who die by suicide were more likely than those without co-morbidities to self-poison with non-psychotropic medications.

METHODS

We analysed data on 14,648 psychiatric patients who died by suicide in England & Wales during 2004-2015, as recorded by the National Confidential Inquiry into Suicide and Safety in Mental Health. Using logistic regression models adjusted for age, gender, ethnicity, and primary drug dependence/misuse we compared patients diagnosed with physical co-morbidities versus those without to assess whether a greater proportion of the former had died by overdose, and medication prescribed to treat such disorders (e.g. opioids, insulin).

RESULTS

24% (n = 3525) were recorded as having physical co-morbidity. A greater proportion of these individuals died by self-poisoning than those without physical co-morbidity (37% vs. 20%, p < .001; adjusted OR 2.47; 95% CI 2.26-2.70), and they were more likely to have used medications for a physical health disorder in overdose (50% vs. 34%; adjusted OR 2.10; 95% CI 1.80-2.46), particularly opioids (30% vs. 22%; p < .001), paracetamol/opioid compounds (11% vs. 7%, p < .001) and insulin (4% vs. 1%, p < .001).

LIMITATIONS

Use of survey data may have resulted in under-reporting of physical health problems and/or overdose medications.

CONCLUSIONS

Overdose, rather than hanging, is the leading cause of suicide among psychiatric patients with physical co-morbidities, particularly using non-psychotropic medications. There is potential for means restriction in preventing suicide among these patients.