According to a study, “A Temporal Evaluation of Antiepileptic Drugs and Suicidality: Is it the Medication or the Comorbidity?” [1]:
While individuals with antiepileptic drug exposure had higher likelihood of suicide related behavior, the trend started before the antiepileptic drug exposure and was not differentially associated with epilepsy status or antiepileptic drug type received.
[The study] compared trends of suicide related behavior before and after initiation of antiepileptic drug therapy among antiepileptic drug users with and without epilepsy to individuals without antiepileptic drug use controlling for sociodemographic characteristics and mental health comorbidity.
Given the limited information available on depression severity in this administrative data it is possible that the significant effect for antiepileptic drug exposure is due to residual confounding of mental health comorbidity.