Clinical Summary: Common Methods of Suicide and Self-Inflicted Poisoning/Injury by Individuals With Major Depressive Disorder and Bipolar Disorder: A Nationwide Inpatient Sample Analysis
Patients with major depressive disorder and bipolar disorder face a suicide risk over 30 times higher than the general population, but the methods used in hospital-treated self-harm are not the same across diagnoses. Knowing which methods are most common in each group can sharpen inpatient risk assessment and means-restriction counseling at discharge.
Key Findings
- Suicide and self-inflicted poisoning/injury by cutting and piercing instruments was common in both groups and was more prevalent in BD than MDD (35.5% vs 30.8%, P < .001).
- Compared with BD, MDD admissions more often involved analgesics (16.7% vs 11%, P = .000), hanging by strangulation and suffocation (3.7% vs 2.5%, P < .001), other sedatives and hypnotics (4.9% vs 3.7%, P < .001), and other and unspecified solid and liquid substances (3.9% vs 3.3%, P = .037).
- Some overdose methods were similarly frequent in both groups, including tranquilizers/other psychotropic agents (29.2% vs 29.4%, P = .72) and other specified drugs and medicinal substances (14.3% vs 14.0%, P = .546).
- Anxiety disorders and adjustment disorders were more prevalent in MDD than BD: 41.7% vs 39.7% (OR = 0.920, CI, 0.864–0.981, P = .011) and 2.3% vs 1.2% (OR = 0.498, CI, 0.386–0.644, P < .001), respectively.
- BD admissions had higher rates of schizophrenia and other psychotic disorders and personality disorders than MDD admissions: 6.1% vs 2.6% (OR = 2.486, CI, 2.125–2.909, P = .000) and 27.5% vs 18.5% (OR = 1.670, CI, 1.548–1.802, P = .000), respectively.
Among hospitalized adults with mood disorders, cutting and piercing instruments were the most common self-harm method in both diagnoses, with higher prevalence in bipolar disorder, while major depressive disorder showed relatively greater use of analgesics, sedatives/hypnotics, and hanging. Suicide risk assessment should be diagnosis-informed and include specific review of access to the methods most commonly used in each group.
Practice Implications
- Ask directly about access to cutting instruments in both MDD and BD, since this was the most prevalent method in both groups and was higher in BD (35.5% vs 30.8%, P < .001).
- In MDD, review access to analgesics, other sedatives and hypnotics, and ligature means because these methods were more common than in BD (16.7% vs 11%, P = .000; 4.9% vs 3.7%, P < .001; 3.7% vs 2.5%, P < .001).
- Do not assume overdose patterns differ across all medication categories; tranquilizers/other psychotropic agents were common and nearly identical in MDD and BD (29.2% vs 29.4%, P = .72).
- Use comorbidity patterns to refine inpatient assessment: prioritize anxiety and adjustment symptoms in MDD, and screen carefully for psychotic and personality pathology in BD given the higher prevalence of schizophrenia and other psychotic disorders (6.1% vs 2.6%) and personality disorders (27.5% vs 18.5%).
