Is Depression Related to Low Folate Levels in People with Epilepsy? An Observational Study and Meta-analysis

BACKGROUND: Both depression and low serum levels of folate are common in people with epilepsy (PWE), the latter especially in patients on hepatic enzyme-inducing antiepileptic drugs (AEDs). We did a cross-sectional study and a meta-analysis to assess if lower folate levels have any relation with depression in PWE. MATERIALS AND METHODS: Two hundred and one PWE were recruited and assessed for depression using the Inventory of Depressive Symptomatology-Self-Rated (IDS-SR) and Inventory of Depressive Symptomatology-Clinician Rated; serum folate levels were measured in them at the same time. Literature search was carried out and studies with data on depression as well as folate levels in PWE were included. Statistical analysis to determine frequency of depression, low folate levels, and relation between them among our cases and the pooled data from the included studies was done. RESULTS: Depression was observed in 65.68% and low serum folate (<4 ng/ml) in 48.75% of PWE (over 80% on older AEDs); there was no statistically significant correlation between them. However, on analyzing the pooled data of six studies including the present, the Fisher's z-transformed correlation coefficient was −0.1690 (95% confidence interval [−0.3175, −0.0124], P = 0.0464). CONCLUSIONS: Depression and low folate levels are common in PWE. Low folate levels have a mild but significant negative correlation with depression in this population, and folate supplementation would be advisable for those on the older AEDs.