During a suicide risk assessment workshop, the faculty asks residents to identify the most common psychiatric diagnosis associated with completed suicide. Which of the following is the most frequent primary psychiatric disorder in individuals who die by suicide?

Explanation

## Psychiatric Diagnoses and Suicide Risk **Key Point:** Major depressive disorder (MDD) is the single most common psychiatric diagnosis in individuals who complete suicide, accounting for 40–60% of all suicide deaths. Depression is present in the majority of suicides, either as a primary diagnosis or as a comorbid condition. ### Prevalence of Psychiatric Diagnoses in Suicide | Diagnosis | % of Completed Suicides | Relative Risk | Key Feature | |-----------|------------------------|---------------|-------------| | **Major Depressive Disorder** | 40–60% | 15–20× | Most common; present in majority | | **Bipolar Disorder** | 10–15% | 20–25× | Highest relative risk per diagnosis | | **Schizophrenia** | 5–10% | 10–15× | Longer illness duration; command hallucinations | | **Substance Use Disorder** | 30–40% | 10× | Often comorbid with depression | | **Personality Disorders** | 5–10% | 5–10× | Usually comorbid; borderline highest | | **Anxiety Disorders** | 10–20% | 5–10× | Often comorbid with depression | **High-Yield:** The distinction between **prevalence** (how common the diagnosis is among suicides) and **relative risk** (how much the diagnosis increases suicide risk) is critical: - **MDD:** Most prevalent (40–60%) but moderate relative risk (15–20×) - **Bipolar disorder:** Less prevalent (10–15%) but highest relative risk (20–25×) - **Schizophrenia:** Least prevalent (5–10%) but moderate relative risk (10–15×) ### Why MDD is Most Common 1. **Prevalence in population:** MDD is the most common mental disorder (~5–10% lifetime prevalence) 2. **Severity of depressive symptoms:** Hopelessness, anhedonia, guilt, and suicidal ideation are core features 3. **Untreated depression:** Many individuals with MDD remain undiagnosed or untreated 4. **Comorbidity:** Depression frequently co-occurs with substance abuse, anxiety, and personality disorders 5. **Chronicity:** Recurrent depressive episodes increase cumulative suicide risk **Clinical Pearl:** In clinical practice, the presence of *depressive symptoms* (not necessarily a formal MDD diagnosis) is the strongest modifiable risk factor for suicide. Treating depression is the most evidence-based intervention to reduce suicide risk. ### Suicide Risk by Diagnosis: Relative Risk Hierarchy ```mermaid flowchart TD A[Psychiatric Diagnosis]:::outcome --> B{Which diagnosis<br/>highest relative risk?}:::decision B -->|Bipolar Disorder| C[Relative Risk 20-25×]:::urgent B -->|Schizophrenia| D[Relative Risk 10-15×]:::urgent B -->|Major Depression| E[Relative Risk 15-20×]:::urgent B -->|Substance Use| F[Relative Risk 10×]:::urgent B -->|Personality Disorder| G[Relative Risk 5-10×]:::action C --> H[BUT less prevalent<br/>in population]:::outcome E --> I[MOST prevalent<br/>in suicide deaths]:::outcome ``` **Mnemonic - Psychiatric Diagnoses in Suicide: BIPODS** - **B**ipolar disorder (highest relative risk, 20–25×) - **I**ntoxication/substance use (30–40% comorbid) - **P**ersonality disorders (especially borderline) - **O**ther anxiety disorders (comorbid with depression) - **D**epression (most common, 40–60%) - **S**chizophrenia (command hallucinations, paranoia) ### Depressive Symptoms Associated with Suicide - **Hopelessness** (stronger predictor than depression severity) - **Anhedonia** (loss of pleasure) - **Guilt and self-blame** - **Psychomotor agitation or retardation** - **Sleep disturbance** - **Concentration difficulties** - **Suicidal ideation with intent and plan** [cite:Kaplan & Sadock's Comprehensive Textbook of Psychiatry 11e Ch 28; Harrison 21e Ch 397]