From the Toronto Star:
http://www.thestar.com/News/article/213298
from the article above:
Brodsky explains that the Crown’s expert prison psychiatrist, Dr. Duncan Scott, has told him and the Crown “that Tony Rosato is certifiable.” Scott’s diagnosis, says Brodsky, is a mental illness called Capgras syndrome. Named for its discoverer, French psychiatrist Jean Marie Joseph Capgras, the syndrome is characterized by the delusion that a person or people have been replaced by doubles or impostors. The rare condition is most commonly associated with schizophrenia, but according to Dr. Graham Glancy, a forensic psychiatrist with Metro West Detention Centre and Maplehurst Correctional Complex, it can also be caused by metabolic diseases, delirium, brain injury or drugs such as cocaine.
It sounds like you answered you own question!