The research study emerged after neurosurgeons noticed that patients with brain injuries who had been prescribed antidepressants were doing better in unexpected ways than other patients with a similar diagnosis who were not prescribed the medication.
“We saw these patients improving in multiple ways — their depression was improved, but so were their memory and cognitive functioning. We wanted to look at the issue more, so we went back to the laboratory to investigate it further,” said Jason Huang, M.D., associate professor of neurosurgery and chief of neurosurgery at the University of Rochester Medical Center.
Huang said many patients who have a traumatic brain injury also experience depression — by some estimates, half of such patients are depressed.
Doctors aren’t sure whether the depression is a byproduct of the sudden, unfortunate change in circumstances that patients find themselves in, or whether the depression is a direct consequence of brain damage.
Previous research by other groups indicated that antidepressants help generate new brain cells and keep them healthy in healthy animals. This finding coupled with the experience of his patients led Huang to study the effects of the antidepressant imipramine (also known as Tofranil) on mice that had injuries to their brains.
Experiments on mice showed that imipramine increased the number of nerve cells in the hippocampus, the part of the brain primarily responsible for memory.
By one measure, mice treated with imipramine had approximately 70 percent more neurons after four weeks than mice that did not receive the medication.
Researchers also discovered the mice given imipramine performed better on memory tests. They were more likely to remember objects they had seen previously and so spent more time exploring truly novel objects, compared to mice that did not receive the compound.
The benefits did not extend to the motor skills of the mice – a finding that parallels what neurosurgeons like Huang have seen in their patients on antidepressants, who don’t show improved mobility after use of the medications.
Scientists aren’t sure whether the drug helps spur the creation of more new neurons, or whether it helps newly created neurons survive – or both. However, researchers have discovered that after a brain injury, the brain appears to create more brain cells, possible as a way to compensate for injury.
“It’s exciting that the study involves a drug that is already safe and approved by FDA and is used clinically. If we could add a medication to the treatment regimen – even a slight improvement would be a big gain for these patients. It’s our hope that the work will ultimately make a difference in patient care,” added Huang.
The team’s findings were published online recently in the Journal of Neurotrauma.
Source: University of Rochester