How have the treatment approaches changed over time regarding the GAD disorder?

–Background/history of treatment- CBT history of GAD disorder. How have the treatment approaches changed
over time regarding the GAD disorder?
–Appropriateness of treatment for the population being discussed. Focusing on prevalence rates in Canadian
society. When does onset happen, is there any population that is more vulnerable to the GAD disorder, etc.
Research focuses on the most current information, past 5 to 10 years, except when citing seminal works, e.g.
Beck, etc.
I prefer a Canadian writer, please, because of the subject.
I do not need a title page, but I need a reference page. I need 4 pages, not including a reference page. Masters
level.