Sociodemographic and clinical risk factors for suicidal ideation and suicide attempt in functional/dissociative seizures and epilepsy: a large cohort study.

Background: People with functional/dissociative seizures (FDS) are at elevated suicidality risk.

Objective: To identify risk factors for suicidality in FDS or epilepsy.

Methods: Retrospective cohort study from the UK's largest tertiary mental healthcare provider, with linked national admission data from the Hospital Episode Statistics. Participants were 2383 people with a primary or secondary diagnosis of FDS or epilepsy attending between 01 January 2007 and 18 June 2021. Outcomes were a first report of suicidal ideation and a first hospital admission for suicide attempt (International Classification of Diseases, version 10: X60-X84). Demographic and clinical risk factors were assessed using multivariable bias-reduced binomial-response generalised linear models.

Findings: In both groups, ethnic minorities had significantly reduced odds of hospitalisation following suicide attempt (OR: 0.45-0.49). Disorder-specific risk factors were gender, age and comorbidity profile. In FDS, both genders had similar suicidality risk; younger age was a risk factor for both outcomes (OR: 0.16-1.91). A diagnosis of depression or personality disorders was associated with higher odds of suicidal ideation (OR: 1.91-3.01). In epilepsy, females had higher odds of suicide attempt-related hospitalisation (OR: 1.64). Age had a quadratic association with both outcomes (OR: 0.88-1.06). A substance abuse disorder was associated with higher suicidal ideation (OR: 2.67). Developmental disorders lowered the risk (OR: 0.16-0.24).

Conclusions: This is the first study systematically reporting risk factors for suicidality in people with FDS. Results for the large epilepsy cohort complement previous studies and will be useful in future meta-analyses.

Clinical implications: Risk factors identified will help identify higher-risk groups in clinical settings.