Psychiatric co-morbidities and factors associated with psychogenic non-epileptic seizures: a case-control study

Psychogenic non-epileptic seizures (PNES) offer an immense diagnostic and therapeutic challenge. We sought to determine socioeconomic, psychological and demographic factors in PNES compared to age and gender matched epilepsy patients as well as healthy controls. We also examined psychiatric co-morbidities in PNES and epilepsy patients.

We conducted a case-control study at a tertiary centre in India with three groups including PNES only, age and gender matched epilepsy only and healthy participants. Factors including marital status, family type, education level and psychiatric comorbidities etc. were compared between the three groups. Details of PNES semiology, duration of event and disease were collected. Psychiatric assessment included MINI International Diagnostic Interview based on DSM-IV criteria and Holmes-Rahe Social Readjustment Scale for stress evaluation. The modified Kuppuswamy scale was used to assess socio-economic status.

We enrolled 100 PNES patients (mean age 26.1 ± 10.8 years), 100 epilepsy patients (23.5 ± 9.6 years) and 100 healthy controls (28.9 ± 11.0 years). Ninety per cent of participants were female. Significant factors associated with PNES included family history of epilepsy [OR 20.3 (2.6-155.6) (p = 0.004)], low education including literate/illiterate status [OR 14.1 (2.5-78.9) (p = 0.003)], interpersonal conflict [OR 2.4 (1.1-6.0) (p = 0.05)] and presence of psychiatric comorbidity [OR 60.5 (24.1-152.2) (p < 0.001)] of which major depression was the most common. The current suicide risk was significantly elevated in PNES compared to epilepsy patients (p < 0.001). PNES disease duration correlated with presence of current depression, dysthymia and suicidality but not with other psychiatric comorbidities.

Our results highlight that several socio-economic and demographic factors are associated with occurrence of PNES. High rates of psychiatric comorbidities including current suicide risk emphasise the need for a collaborative neuropsychiatric approach.