Psychosis rarely occurs in patients with late-onset focal epilepsy

We examined psychosis occurrence in patients with late-onset focal epilepsy.

Case records of consecutive patients with focal epilepsy without central nervous system (CNS) disease (n = 873) were retrospectively examined, with gender, age at epilepsy onset, duration of epilepsy, epilepsy type (temporal or extratemporal), and age at the initial examination used as clinical and demographic variables. Patients with onset ≤49 years old (control) were compared with those with late-onset.

In the control group (n = 775), 38 had a history of psychosis, while none in the late-onset group (n = 98) reported that (p = 0.016). Psychosis was only interictal in 32 and predominantly postictal in 6, while 2 patients showed both interictal and postictal psychosis. Duration of illness (p = 0.000001) and temporal lobe epilepsy (p = 0.000343) were significant determinants associated with psychosis. Gender (p = 0.210) and age at examination (p = 0.084) were found to be not contributory to psychosis.

The prevalence for a history of psychosis in the present cohort (2.5%) agrees well with that noted in previous studies, and duration of illness proved to be the most powerful determining factor leading to that. A keen awareness of unrecognized underlying CNS or metabolic disease is important when psychosis appears in patients with nonlesional late-onset epilepsy, which should lead to an in-depth investigation of possible underlying and still uncovered CNS disease.