Self-poisoning and self-injury have widely differing incidences in hospitals and in the community, which has led to confusion about the concept of self-harm.
Categorising self-harm simply by a method may be clinically misleading because many hospital-attending patients switch from one method of harm to another on subsequent episodes. The study set out to determine the frequency, pattern, determinants and characteristics of method-switching in self-harm episodes presenting to the general hospital.
The pattern of repeated self-harm was established from over 33,000 consecutive self-harm episodes on a multicentre English cohort, categorising self-harm methods as poisoning, cutting, other injury, and combined methods.
Over an average of 30 months of follow-up, 23% of people repeated self-harm and one-third of them switched method, often rapidly, and especially where the person was male, younger, or had self-harmed previously. Self-poisoning was far less likely than other methods to lead on to switching.
Self-harm episodes that do not lead to hospital attendance are not included in these findings but people who self-harmed and went to hospital but were not admitted from the emergency department the general hospital, or did not receive designated psychosocial assessment are included. People in the study were a mix of prevalent as well as incident cases.
Method of self-harm is fluctuating and unpredictable. Clinicians should avoid false assumptions about people’s risks or needs based simply on the method of harm.