Poisoning substances taken by young people: a population-based cohort study

Abstract

Background: Globally, poisonings account for most medically-attended self-harm. Recent data on poisoning substances are lacking, but are needed to inform self-harm prevention.

Aim: To assess poisoning substance patterns and trends among 10-24-year-olds across England DESIGN AND SETTING: Open cohort study of 1 736 527 young people, using linked Clinical Practice Research Datalink, Hospital Episode Statistics, and Office for National Statistics mortality data, from 1998 to 2014.

Method: Poisoning substances were identified by ICD-10 or Read Codes. Incidence rates and adjusted incidence rate ratios (aIRR) were calculated for poisoning substances by age, sex, index of multiple deprivation, and calendar year.

Results: In total, 40 333 poisoning episodes were identified, with 57.8% specifying the substances involved. The most common substances were paracetamol (39.8%), alcohol (32.7%), non-steroidal anti-inflammatory drugs (NSAIDs) (11.6%), antidepressants (10.2%), and opioids (7.6%). Poisoning rates were highest at ages 16-18 years for females and 19-24 years for males. Opioid poisonings increased fivefold from 1998-2014 (females: aIRR 5.30, 95% confidence interval (CI) = 4.08 to 6.89; males: aIRR 5.11, 95% CI = 3.37 to 7.76), antidepressant poisonings three-to fourfold (females: aIRR 3.91, 95% CI = 3.18 to 4.80, males: aIRR 2.70, 95% CI = 2.04 to 3.58), aspirin/NSAID poisonings threefold (females: aIRR 2.84, 95% CI = 2.40 to 3.36, males: aIRR 2.76, 95% CI = 2.05 to 3.72) and paracetamol poisonings threefold in females (aIRR 2.87, 95% CI = 2.58 to 3.20). Across all substances poisoning incidence was higher in more disadvantaged groups, with the strongest gradient for opioid poisonings among males (aIRR 3.46, 95% CI = 2.24 to 5.36).

Conclusion: It is important that GPs raise awareness with families of the substances young people use to self-harm, especially the common use of over-the-counter medications. Quantities of medication prescribed to young people at risk of self-harm and their families should be limited, particularly analgesics and antidepressants.

Keywords: adolescent; general practice; poisoning; self-injurious behavior; young adult.

Figure 1.

Number of poisoning codes and events.

Figure 2.

Incidence rates by age over time for a) poisonings involving paracetamol in males, b) poisonings involving paracetamol in females, c) poisonings involving aspirin/NSAIDs in males, d) poisonings involving aspirin/NSAIDs in females, e) poisonings involving opioids in males, f) poisonings involving opioids in females. g) poisonings involving antidepressants in males, h) poisonings involving antidepressants in females, i) poisonings involving alcohol in males, j) poisonings involving alcohol in females, k) unspecified substance poisonings in males, l) unspecified substance poisonings in females.

Figure 2.

Incidence rates by age over time for a) poisonings involving paracetamol in males, b) poisonings involving paracetamol in females, c) poisonings involving aspirin/NSAIDs in males, d) poisonings involving aspirin/NSAIDs in females, e) poisonings involving opioids in males, f) poisonings involving opioids in females. g) poisonings involving antidepressants in males, h) poisonings involving antidepressants in females, i) poisonings involving alcohol in males, j) poisonings involving alcohol in females, k) unspecified substance poisonings in males, l) unspecified substance poisonings in females.