PSYCHIATRIC MORBIDITY IN EPILEPSY - A CASE-CONTROLLED STUDY OF ADULTSRECEIVING DISABILITY BENEFITS

Objective-To compare the prevalence of non-organic psychiatric disorde rs among disabled patients of normal intelligence with epilepsy with t he prevalence of similar psychiatric disorders among age and sex match ed disabled patients with other somatic diseases. Methods-A case-contr ol study was carried out in Iceland among people receiving disability benefits using information available at the State Social Security Inst itute. There were 344 patients with epilepsy in Iceland 16 to 66 years of age (inclusive) receiving disability benefits in 1995, By excludin g mentally retarded patients, autistic patients, and patients with org anic psychoses, 241 index cases with epilepsy qualified for the study, For each case two age and sex matched controls were selected from all patients receiving disability benefits who had cardiovascular disease s, respiratory diseases, or arthropathies, The same exclusion criteria were applied to the controls as the index cases, In both patient grou ps psychiatric diagnoses were classified into one of the four followin g categories: (1) psychotic illness; (2) neurotic illness or personali ty disorders; (3) alcohol or drug dependence or misuse; and (4) other mental-disorders. Results-Psychiatric diagnosis was present among 35% (85/241) of the cases compared with 30% (143/482) of the controls (p=0 .15). There was a difference in the distribution of the two groups int o different psychiatric categories (p=0.02). This was mainly due to an excess of men in the index group with psychosis, particularly schizop hrenia or paranoid states. Conclusion-The results suggest that there i s not a difference in the prevalence of non-organic psychiatric disord ers among disabled patients of normal intelligence with epilepsy compa red with patients with other disabling somatic diseases, However, the data indicate that when psychopathology is present disabled patients w ith epilepsy are more likely to have psychotic illness than the other disabled patients.