Effects of Lamotrigine on Mood in Older Adults with Epilepsy and Co-Morbid Depressive Symptoms

Background: Both epilepsy and depressive symptoms are more prevalent in older individuals than in any other age group. Furthermore, depressive symptoms are among the most common interictal psychiatric co-morbid disorders in people with epilepsy. For these reasons, pharmacological treatment of epilepsy that might also confer antidepressant effects may be particularly beneficial in older patients. In this respect, lamotrigine is of considerable interest amongst antiepileptic drugs (AEDs) because it has proven thymoleptic activity.

Objective: These analyses, conducted on a data set drawn from a previously reported, open-label, multicentre, prospective study, examined the effect of lamotrigine on mood in adults aged ≥50 years with epilepsy and co-morbid depressive symptoms. All subjects were receiving background AED therapy at baseline.

Methods: Of the 158 subjects enrolled in the initial study, 40 adults (24 women, 16 men) met the age criterion for these analyses. The study consisted of a screening/baseline phase and four treatment phases over 36 weeks: lamotrigine escalation phase (7 weeks); lamotrigine maintenance or adjunctive therapy phase (12 weeks); concomitant AED withdrawal phase (5 weeks); and lamotrigine monotherapy phase (12 weeks). Psychometric evaluation of mood utilized the Beck Depression Inventory (BDI-II), Center for Epidemiological Studies Depression Scale (CES-D), the Neurological Disorders Depression Inventory in Epilepsy (NDDI-E) and the Profile of Mood States (POMS). Scores at the end of the adjunctive and monotherapy phases were compared with baseline scores. Lower scores on these scales indicate less depressive symptomatology.

Results: Mean baseline scores for the BDI-II, CES-D, NDDI-E and POMS were 15.8, 24.3, 13.8 and 57.7, respectively. Change scores were statistically significant (p < 0.01) compared with baseline at the end of the adjunctive and monotherapy phases for all four psychometric measures of mood, with the exceptions of BDI-II and NDDI-E at the end of the adjunctive phase.

Conclusions: The older adults in these analyses presented with low to moderate levels of depressive symptoms. Addition of lamotrigine to background AED therapy demonstrated antidepressant activity similar to that for the whole sample in the initial study. Given that the onset and prevalence of epilepsy are higher in older adults than in any other age group, pharmacological treatment for epilepsy in older patients that might also confer antidepressant therapy may be particularly beneficial.