Thank you for the article on psychiatric disorders in MS. My brother had primary-progressive MS for the last 10 years of his life. Before this disease, he was one of the most forgiving and friendly people I have ever known. After developing MS, he began to have intense bursts of anger. As I was one of his caregivers, this hurt me. He always felt bad about it and apologized. I assumed it was due to the frustration of this active man being confined to a wheelchair. Now I wonder whether his outbursts were caused by pseudobulbar affect.