Assessing the frequency of epilepsy and depression from selected clinic samples gives a bias toward the more severely affected patients and also those on the most medication. A better understanding of comorbid psychopathology should come from community studies. Edeh and Toone (1987) carried out a general practice study in the United Kingdom and reported that 22% of unselected patients with epilepsy were rated as having a depressive disorder. A Canadian Community Health Survey examined 253 people with epilepsy using a rating scale to identify a history of depression, and noted a lifetime prevalence of depression at 22%: this was compared with 12% in the general population (Tellez-Zenteno et at, 2005).
Psychiatric Controversies in Epilepsy
Copyright © 2008 by Elsevier Inc. All rights of reproduction in any form reserved.
More recently, Ettinger et al. (2004) assessed depression in 775 people with epilepsy, and compared the incidence with patients with asthma, and also healthy controls. In this study, a rating scale assessment was again used (Centers of Epidemiological Studies — Depression Instrument). Symptoms of depression were significantly more frequent in the epilepsy group (36.5%) in comparison with those with asthma (27.8%) and the controls.
Several studies have noted a correlation with seizure frequency. In an epidemiological study, Jacoby et al. (1996) noted that depression occurred in 4% of seizure-free patients, in 10% of patients with less than one seizure a month, but at a rate of 21% in patients with higher seizure frequency. O'Donoghue et al. (1999) noted that patients with epilepsy with continuing seizures were significantly more likely to suffer from depression than those in remission (33% vs. 6%).
There are a number of studies from selected patient groups, for example tertiary centers, or from those awaiting surgery for epilepsy, which note in these populations an even higher frequency of depression. Victoroff et al. (1994) evaluated 60 patients with intractable complex partial seizures using a structured clinical interview for Diagnosis and Statistical Manual (DSM)-IIIR diagnoses, and observed that 58% had histories of depressive disorders. Jones et al. (2005a) examined 199 patients from five epilepsy centers, again using structured clinical interview techniques and noted 34% to meet criteria for a mood or anxiety disorder, and 19% to meet criteria for major depression. Ring et al. (1998) examined 60 patients awaiting temporal lobe epilepsy surgery, and noted at preoperative assessment that a major depressive disorder was present in 21%. These data suggest that we know that epilepsy and depression are commonly linked together, an association found more frequently than in some other chronic disorders such as asthma. We also know that the relationship of depression is greater in those with higher seizure frequencies and with continuing seizures.
Thus, the presence of depression can be said to be even greater in selected populations that most likely reflects in a large part on the intractability of the seizure disorders.
Another finding, which has been verified, is the association between depressive symptomatology and quality of life in people with epilepsy. Gilliam et al. (1997) noted depressive symptoms to be the most important predictor of quality of life, and these were a more powerful predictor than the actual seizure frequency. Perrine et al. (1995) and Boylan et al. (2004) have reported similar findings.
Was this article helpful?