Summary:Purpose: To describe the epidemiology of somatic and psychiatric conditions in adults with epilepsy in the community and compare it to that of people without epilepsy.Methods: A cross-sectional population-based study extracting data from the UK General Practice Research Database for the period 1995-1998. Age-and sex-standardized prevalence rates were estimated for selected conditions and groups of conditions (categorized by ICD-9 chapters) in adults with epilepsy registered with primary care physicians. Results were compared with those in adults without epilepsy in the cohort, and prevalence ratios were calculated according to two broad age groups (16-64 and older than 64 years).Results: Conditions common in the general population also were common in adults with epilepsy. Psychiatric disorders occurred twice as often, and the risk of somatic disorders was increased in people with epilepsy, with the exception of musculoskeletal and connective tissue disorders in older adults. The prevalence ratio of neoplasia, excluding intracranial tumors, was not increased in epilepsy. The prevalence ratio of brain tumors was particularly increased in young adults [prevalence ratio (PR), 70.7] and of meningiomas in older adults (PR, 91.9). Neurodegenerative conditions, particularly dementias and Alzheimer' disease (PR, 6.3 and 8, respectively) and Parkinson' disease (PR, 3.2), appeared more frequently in people with epilepsy. Upper gastrointestinal bleed occurred more frequently in epilepsy (PR, 4.3), as did cardio-and cerebrovascular disorders, fractures, pneumonia and chronic lung diseases, and diabetes. Eczema, osteoarthritis, and rheumatoid arthritis did not occur more frequently in epilepsy.Conclusions: The prevalence ratio of many common psychiatric and somatic conditions is increased in adults with epilepsy who consult a primary care physician in the U.K. These findings may have implications in the diagnosis and management of epilepsy and coexisting conditions, as well as in health care provision.

Several studies have assessed the prevalence of psychiatric disorders in epilepsy. They are characterized by considerable heterogeneity, because of differences in the population setting and type of study. A non-systematic review of the literature allows us to draw some useful, although not definite, conclusions. Six per cent of people with epilepsy in the general population appear to suffer from a psychiatric disorder, while this rises to 10-20% in populations with temporal lobe and/or refractory epilepsy. Mood disorders are the most common culprit (24-74%), particularly depression (30%), followed by anxiety disorders (10-25%), psychoses (2-7%) and personality disorders (1-2%). This comorbidity appears to be related to endogenous and exogenous (including iatrogenic) factors and to the severity and chronicity of epilepsy. Conditions such as schizophrenia-like psychosis of epilepsy and interictal dysphoric disorder are represented only in epilepsy. Adequate recognition and treatment of psychiatric conditions in epilepsy is essential for patient management because of their considerable burden in morbidity and quality of life.

SUMMARYA range of medical and neurologic disorders occurs more frequently in people with epilepsy than in the general population and constitutes its somatic comorbidity. Common examples include cardiac, gastrointestinal, and respiratory disorders; stroke; dementia; and migraine. Alzheimer's disease and migraine are not only more common in epilepsy but are also risk factors for the development of seizures, suggesting a bidirectional association and shared disease mechanisms. Less well-appreciated associations with epilepsy include Parkinson's disease and obstructive sleep apnea. The association between epilepsy and other conditions can be due to a variety of interacting genetic, biologic, and environmental factors. We propose an etiologic classification of comorbidity into uncertain (coincidence or unknown), causal (cause), shared risk factors (common disease mechanisms or shared predisposing risk factors), and resultant (consequence). Co-occurrence of other conditions in a person with epilepsy can complicate diagnosis or have adverse prognostic implications. Management of these conditions may facilitate the treatment of epilepsy, as in the case of obstructive sleep apnea. The presence of somatic disorders in epilepsy is associated with increased health care needs, poorer health-related quality of life, and premature mortality. Prevention, identification, and adequate treatment of comorbid disorders in epilepsy should be an important part of epilepsy management at all levels of care.