Epilepsia, 48(12):2336–2344, 2007 doi: 10.1111/j.1528-1167.2007.01222.x FULL-LENGTH ORIGINAL RESEARCH Psychiatric comorbidity in epilepsy: A population-based analysis * Jose F. Tellez-Zenteno, †Scott B. Patten, ‡Nathalie Jett ´ e, †Jeanne Williams, and ‡Samuel Wiebe * Division of Neurology, University of Saskatchewan, Saskatoon, Saskatchewan; and Departments of †Community Health Sciences and ‡Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada SUMMARY Purpose: The estimated prevalence of mental health disorders in those with epilepsy in the general population varies owing to differences in study methods and heterogeneity of epilepsy syn- dromes. We assessed the population-based preva- lence of various psychiatric conditions associated with epilepsy using a large Canadian national pop- ulation health survey. Methods: The Canadian Community Health Sur- vey (CCHS 1.2) was used to explore numerous aspects of mental health in persons with epilepsy in the community compared with those without epilepsy. The CCHS includes administration of the World Mental Health Composite International Di- agnostic Interview to a sample of 36,984 subjects. Age-specific prevalence of mental health condi- tions in epilepsy was assessed using logistic regres- sion. Results: The prevalence of epilepsy was 0.6%. In- dividuals with epilepsy were more likely than indi- viduals without epilepsy to report lifetime anxiety disorders or suicidal thoughts with odds ratio of 2.4 (95% CI = 1.5–3.8) and 2.2 (1.4–3.3), respectively. In the crude analysis, the odds of lifetime major de- pression or panic disorder/agoraphobia were not greater in those with epilepsy than those without epilepsy, but the association with lifetime major depression became significant after adjustment for covariates. Conclusions: In the community, epilepsy is associ- ated with an increased prevalence of mental health disorders compared with the general population. Epilepsy is also associated with a higher prevalence of suicidal ideation. Understanding the psychiatric correlates of epilepsy is important to adequately manage this patient population. KEY WORDS: Epilepsy—Psychiatric comorbidity —Depression—Anxiety disorders—Mood disord- ers—Substance abuse—Suicidal ideation—Health surveys—Population-based. Originally coined by Feinstein, the term comorbidity is used to refer to the greater than coincidental association of two conditions in the same individual (Feinstein, 1970). The psychiatric comorbidities in people with epilepsy have important clinical and therapeutic implications. Preva- lence studies on the association between epilepsy and psy- chiatric disorders have found that epilepsy can precede, co-occur with or follow the diagnosis of a psychiatric dis- order (Gaitatzis et al., 2004a). The most frequent psychi- atric diagnoses reported in people with epilepsy include Accepted May 21, 2007; Online Early publication July 30, 2007. Address correspondence and reprint requests to Dr. Samuel Wiebe, Di- vision of Neurology, Foothills Medical Centre, 1403–29 St. NW, Calgary, Alberta, Canada, T2 N 2T9. E-mail: swiebe@ucalgary.ca Blackwell Publishing, Inc. C  2007 International League Against Epilepsy psychoses, neuroses, mood disorders (DSM-IV axis I dis- orders), personality disorders (DSM-IV axis II disorders), and behavioral problems (Gaitatzis et al., 2004a). Psychi- atric symptoms can be classified according to their tem- poral relationship with seizure occurrence. They can be di- vided into peri-ictal symptoms (related to the seizure itself) or interictal symptoms (independent of seizures). Peri-ictal symptoms can precede the seizure (pre-ictal), occur dur- ing a seizure itself (ictal), or follow the seizure (postictal) (Swinkels et al., 2005). There are few population-based studies evaluating the prevalence of psychiatric conditions in people with epilepsy. Most studies involve selected groups of patients from tertiary centers or specialized clinics. Psychiatric psy- chopathology may be overrepresented in selected popula- tions such as patients with temporal lobe epilepsy or those 2336