Suicide attempts by over the counter drugs

Article in review: Mikhail, A., Tanoli, O., Légaré, G., Dubé, P-A., Habel, Y., Low, N.,  … & Rahme E. (2019). Over-the-Counter Drugs and Other Substances Used in Attempted Suicide Presented to Emergency Departments in Montreal, Canada. Crisis, https://doi.org/10.1027/0227-5910/a000545

Summary

Research indicates that over-the-counter medicines are often used in suicide attempts. This Canadian study intended to identify patient characteristics of adults who presented to the hospital for attempted suicide by overdose with over-the-counter or prescription drugs, and other methods.

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Suicide by means of overdose

Self-poisoning was the most common method of suicide attempted by women in Canada in 2009 and the second most common by men. Other studies from Canada and the UK have also found that over-the-counter medicines are the most frequently used substances by those who self-poison. In one English study, toxic ingestions were noted in 80% of suicide attempts.

Controlling access to toxic substances has shown some promise in reducing suicides, including the sale of drugs that could be used for self-poisoning. Restricting access to pesticides in India and acetaminophen in the UK have been shown to reduce overall suicide mortality. Labelling may also reduce the risk of an accidental overdose but it is thought to be unlikely to reduce deliberate overdose. Accessibility, toxicity, and unsupervised access may be moderators for suicide attempts.

Method and study group

Medical records and nursing triage files of individuals who presented at a local hospital for attempted suicide between January 2009 and March 2010 we accessed and analysed. All patients with a known method of suicide attempt were included, while those with an unknown method attempt were not.

The records and files were used to determine first the numbers of patients who had attempted suicide by substances or by other methods, then, further analysed to identify in which cases the substance was an over-the-counter medicine. In cases where there were both over-the-counter and other substances, the cases were included in the over-the-counter group.

The patient characteristics then analysed included:

• Social demographic characteristics – e.g. age, sex marital status, education and work status
• Medical comorbidities – e.g. cancer, hepatitis, HIV and others
• Personal and family history of mental illness
• Prior suicide attempts

In total 369 patient files were considered. In almost half of all of these cases (181 cases or 49%) the suicide attempt involved substances, making it the most common suicide attempt method used. The remainder involved more violent methods.

Findings

Toxicology assessment had been conducted in 92% of the overdose cases involving substances and only 68% of the other cases. An analysis of the recorded identified:

• More patients who overdosed required treatment in the ICU than other cases (24% vs. 13%)
• Fewer patients who overdosed required surgical procedures than in other cases (2% vs. 21%)
• Women were more likely to attempt suicide by overdose than men
• Those with commodities were more likely to attempt suicide by overdose than those without
• The most common medical comorbidities identified were cancer and chronic pain
• Those with diagnosed substance use disorders were more likely to use violent methods that overdose
•  A total of 64% of those who attempted suicide by use of over-the-counter drugs were younger than 34 years of age.

Honing in on the instances of overdose, 85 patients (47%) had at least one over-the-counter drug present. The most frequently used substances by classification were antidepressants, anxiolytics, opioids, and anticonvulsants. The most common drugs were acetaminophen (a pain relief medication) (30%) and diphenhydramine (an antihistamine). The drug diphenhydramine has not been well researched with regard to use in attempted suicide. In the study it was also not routinely looked for, leading authors to believe that its use may be underestimated in this study.

Other drugs identified included ibuprofen, acetylsalicylic acid, and pseudoephedrine. Of the 85 patients who used over-the-counter drugs, 47 used over-the-counter drugs only. Cocaine, ethanol, cannabis, and MDMA were identified as other non-over-the-counter substances.

This study has several benefits, not least emphasizing the importance of a psychosocial-needs-based assessment to understand not only what their needs are, but their plans, intent, and access to means for suicide. Over-the-counter medicines are demonstrated to be frequently used in suicide attempts, and this knowledge can be used to guide decisions about their accessibility and control, which may be particularly relevant to people prescribed a range of medications, together with over-the-counter medicines.