People with schizophrenia are six times more likely to develop epilepsy, says a study which finds a strong relationship between the two diseases.
The study followed around 16,000 patients with epilepsy and schizophrenia between 1999 and 2008.
It has used data from the Taiwan National Health Insurance database and was led by researchers from the China Medical University Hospital in Taichung.
They identified 5,195 patients with schizophrenia and 11,527 patients with epilepsy who were diagnosed during the nine years period.
These groups of patients were compared to groups of the same sex and age who did not have either epilepsy or schizophrenia.
The findings show that the incidence of epilepsy was 6.99 per 1,000 person-years in the schizophrenia patient group compared to 1.19 in the non-schizophrenia group.
This is the first convincing study to suggest that people with schizophrenia could also be at risk of developing epilepsy
The incidence of schizophrenia was 3.53 per 1,000 person-years for patients with epilepsy compared to 0.46 in the non-epilepsy group.
Previous studies had suggested a prevalence of psychosis among epilepsy patients.
Researchers in this study also found that schizophrenia levels were slightly higher in men with epilepsy than in women with the disease.
Dr Manny Bagary, consultant neuropsychiatrist in Birmingham, said it was a “very interesting” study.
“We have been aware that epilepsy sufferers seem to be have an increased risk of psychosis but this is the first convincing study to suggest that people with schizophrenia could also be at risk of developing epilepsy, suggesting a bidirectional relationship has been found between depression and epilepsy”.