People with epilepsy often have depression, which can be quite severe. Is depression a response to the difficulties of living with a chronic disorder, or is it possible that seizures themselves cause depression? An animal study from a group in California (https://www.ncbi.nlm.nih.gov/pubmed/17368107) has suggested that depression may be caused – or made worse – by repeated seizures that start in the brain regions known as the temporal lobes (located on the sides of the brain). The belief is that the seizures themselves cause depression.
Drs. Brian Scott and Carter Snead are trying to replicate this research finding. They are studying whether repeated seizures that start in the temporal lobe structure known as the hippocampus produce “depression-like” behaviours in rats. To induce seizures in rats, they are using a technique known as “kindling”. Kindling involves repeatedly delivering mild electrical stimulation to the brains of rats. Over time, this repeated stimulation makes a seizure more likely to occur.
So far the data suggest that seizures don’t cause depression. Drs. Scott and Snead are now beginning to explore another hypothesis: that depression may make seizures more likely to occur. This would also explain why depression and seizures are closely linked and why depression may sometimes start before epilepsy is diagnosed. Work on this new research question has just begun.