Irritability and aggression are problems that greatly affect the lives of many
people living with traumatic brain injury (TBI) and their families. There has been
little research to help guide physicians on how to best treat these challenging
behaviors. Recent studies suggest that amantadine might have a new use in
helping people with TBI. Amantadine is a medication that has been used for
decades to treat Parkinson ’s disease, prevent viral infections, and promote
recovery from coma after brain injury. Flora Hammond, MD, Chief of Medical
Affairs at Rehabilitation Hospital of Indiana, recently completed a pilot study that
found amantadine reduced irritability and aggression in people suffering from
brain injuries. 76 individuals with chronic TBI were enrolled in a parallel-group,
randomized, double-blind, controlled trial of amantadine (n=38) versus placebo
(n=38). Irritability was measured before and after treatment using the
Neuropsychiatric Inventory (NPI) Irritability and Aggression Domains which
measures the frequency and severity of these problems. NPI-Caregiver Distress
was also measured. Mean change in NPI-I was -4.3 in the amantadine group
and -2.6 in the placebo group (p=0.0085). In the amantadine group 80.56%
improved at least 3 points on the NPI-I, compared to 44.44% who improved at
least 3 points in the placebo group. NPI-Aggression was also significantly
improved. However, mean change in NPI-I Caregiver Distress was not
statistically significant in the amantadine group, as compared to the placebo
group. Thus, amantadine appears to be a beneficial treatment for reducing the
frequency and severity of irritability that accompanies chronic TBI. Based on the
encouraging pilot data, a larger study with several study sites across the United
States is being conducted to confirm these findings that amantadine improves
irritability and aggression often associated with brain injuries. The study is
funded by a $4.2 million grant from the National Institute on Disability and
Rehabilitation Research. “Many individuals with TBI and their families struggle
with irritability and aggression that impacts their day-to-day life through changes
in relationships and difficulties at work,” says Dr. Hammond. “A need for
assistance for these two common problems is needed. With this study we hope
to verify our findings and help individuals and caregivers cope with the
behavioral effects of brain injury.”