Abstracts

Interictal depression is known to be a common comorbid psychiatric disorder in chronic epilepsy, including temporal lobe epilepsy (TLE). Recent research has suggested that in addition to traditional clinical variables such as seizure frequency, co-morbid depressive symptoms may be a major contributor to poorer health-related quality of life (HRQOL) in epilepsy. This investigation attempted to: 1) replicate the reported relationship between interictal depressive symptoms and reduced HRQOL, 2) characterize the relative explanatory power of interictal depressive symptoms versus other pertinent clinical epilepsy (e.g., seizure severity, seizure frequency, duration of epilepsy, monotherapy vs. polytherapy) and sociodemographic factors (gender) known to influence HRQOL in epilepsy, and 3) determine whether interictal depressive symptoms exert comparable effects on other measures of psychosocial status such as life satisfaction.
88 subjects with TLE completed measures of HRQOL (Quality of Life in Epilepsy-89 [QOLIE]) and subjective handicap (Subjective Handicap in Epilepsy Scale [SHE]) from which dependent measures of overall quality of life (QOLIE-89) and life satisfaction (SHE) were derived. Predictor variables included severity of depressive symptoms (Symptom Checklist-90-Revised), seizure severity during the past six months (Liverpool Seizure Severity Scale), duration of TLE (years), overall seizure frequency (daily, weekly, monthly, yearly), monotherapy vs. polytherapy, and gender. Stepwise regression analysis was performed in order to control for collinearity.
The stepwise regression analysis for HRQOL (QOLIE-89) was significant (R²=.59, p[lt] .001). Poorer HRQOL was found to be associated with increased depression (p[lt] .0001), severity of seizures (p[lt].002), and increasing duration of TLE (p[lt].002). The stepwise regression analysis for life satisfaction as measured by the SHE was significant (R² = .37, p[lt] .01). Poorer life satisfaction was found to be associated with increased depression (p[lt].0001). No other variables were significant.
Interictal depressive symptoms, a common co-morbidity in chronic epilepsy, are a significant predictor of HRQOL and life satisfaction among patients with TLE, replicating and extending previous findings (Gilliam, 2002). In addition, chronicity of epilepsy and seizure severity, but not seizure frequency, predict HRQOL. In addition to highlighting the adverse effects of chronic and self-reported severity of seizures, these findings reinforce the importance of identifying and treating interictal depression and depressive symptoms in epilepsy.
[Supported by: NIH NS 2RO1-37738 and MO1 RR03186]