2009
(Abst. 2.149)
Prevalence of co-morbid epilepsy in patients with primary psychiatric disorders: data from the atlantic behavioral health program, a community-based facility
Authors: Jeffrey Politsky, L. Rizutto, F. Tahil and S. Brophy
Rationale:
The prevalence of mood disorders is estimated to be substantially higher in patients with epilepsy than those without epilepsy, ranging from 19 - 62% in epileptics compared with 5-10% in patients without epilepsy. Less is known about the prevalence of bipolar disorder compared with depression. There is also uncertainty as to whether certain psychiatric conditions have a greater or lesser propensity to co-exist with certain types of epilepsy conditions (e.g. depression and partial epilepsy, bipolar disorder and primary generalized epilepsy). When the question is reversed, it is inherently more difficult to answer: that is, what is the prevalence of co-morbid epilepsy in patients with pre-existent psychiatric disorders.
Methods:
In an effort to answer this question, we reviewed the charts of 561 patients assessed in the Division of Behavioral Medicine from 2007-2008. IRB approval for the review was obtained. The diagnosis of epilepsy was divided into definite, probable, possible, and unlikely. The determination of a diagnosis of definite or probable epilepsy was based on a history of seizures during intake, evidence of an abnormal EEG or Video-EEG study characterized by recorded seizures and/or epileptiform discharges. Cases of possible or unlikely epilepsy were based on normal or non-specifically abnormal EEG studies, an unremarkable history, or a history suggestive of non-epileptic events. Univariate and multivariate statistical analyses were performed.
Results:
Less than 15 percent of patients with psychiatric diagnoses that included depressive, bipolar, and anxiety disorders, and other psychiatric conditions (e.g. psychosis) were considered to have definite or probable epilepsy, which is much less than published data for the prevalence of co-morbid mood and anxiety disorders in epilepsy patients. The majority of these patients had mood disorders. This data, however, may not accurately reflect the true prevalence of these co-morbid states for a number of reasons: first, patients with primary psychiatric disorders are often not asked about pre-existent seizure disorders or the information isn’t properly communicated between health care providers; second, many patients with primary mood or anxiety disorders are treated with drugs that are potent anti-seizure medications, which could suppress clinical seizures as well as epileptiform activity; third, few psychiatric patients undergo qualitative testing with EEG or VEEG before, during, or after diagnosis and treatment; and fourth, a percentage of patients interpreted as having seizures on intake, may actually have non-epileptic events.
Conclusions:
The prevalence of co-morbid epilepsy in patients with primary psychiatric disorders is less well studied than the reverse scenario. While the prevalence of epilepsy in patients with psychiatric disorders is higher than in the normal population (without mood disorders) it may still be under-estimated. Further study to evaluate the relationship of co-morbid epilepsy and psychiatric disorders is warranted.