Older adults who are clinically depressed are six times as likely to have a seizure as their happier peers. The finding suggests that -- at least in some cases -- an underlying factor may be the cause of both depression and seizures. Past studies have suggested that depression is more common in epileptics, although it has not been clear if the depression is a cause or an effect of seizures, or if the conditions are possibly related to antiseizure or antidepressant medication.

The researchers examined patient's medical records for major depression, which is characterized by diminished interest in normal activities, weight change, sleeping problems (either too much or too little), suicidal thoughts, difficulty concentrating and feelings of worthlessness or guilt. They found that 6% of patients who had experienced seizures had suffered from major depression prior to their seizure. In comparison, only 1% of the control group, who had not experienced seizures, had suffered from major depression.

While some past studies have suggested that tricyclic antidepressants might increase seizure risk, the findings indicated that the association between such therapies and seizures can be explained almost entirely by major depression.The results offer new insight into the connection between seizures and depression. While epileptics face a higher risk of depression than the general population, depression is not necessarily brought on by the disorder, according to the report. Rather, both conditions might stem from a common neurological cause.

Annals of Neurology February 2000;47:246-248.