Of the 8815 persons studied, 81% were women.
The type of bariatric surgery was a gastric bypass in almost all of them (98.5%).
Four types of self-harm behaviors were recorded: Intentional self-poisoning by medications (ICD-10 X61- 64), Intentional self-poisoning by and exposure to alcohol (X65), Intentional self-poisoning by toxic chemicals (X66-69), and Intentional self-harm by physical trauma (X70-84).
Self-harm emergencies occurred during follow-up in 111 patients. So, the percentage of persons who had a self-harm emergency was 1.3%, relatively low.
But, most importantly, self-harm emergencies increased after surgery (3.6 per 1000 patient-years) compared with before surgery (2.3 per 1000 patient-years).
The most common method used was an intentional overdose (73% of emergencies).
The self-harm emergencies were clinically significant: 54% required ambulance transport to a hospital, 93.0% were classified as urgent, and 54% led to a hospital admission.
93% of the events occurred in persons diagnosed as having a mental health disorder during the 5 years before the surgery.
The mechanisms for increased self-harm after bariatric surgery are not known. The authors speculated on the following possibilities:
1. Changes in alcohol metabolism after surgery may increase the likelihood of alcohol intoxication or alcohol-related disinhibition with impulsivity leading to self-harm after surgery.
2. Increased stress and anxiety in postoperative patients may lead to anxiolytic use or exacerbation of preexisting mental health conditions.
3. The eating behaviors that lead to morbid obesity may be considered to be addictive behaviors, and after surgery, these persons may substitute substance use for food.