Hi, here's my understanding of the professional differences among the different titles according to my experience seeing all of them here in Canada.

1. Psychiatrist - Medical doctor, can prescribe meds, often focuses on medical terminology to describe your situation. Not necessarily trained to support you through your illness, outside of diagnosing your illness according to medical model.

2. Psychologist - Has some level of post-graduate certification (either MA/MSc in psych or PhD), often trained to support clients in a clinical setting, meaning they use a variety of techniques to help you through your symptoms. They do not prescribe meds.

3. Counsellor - Has some level of education in the field of social work or counselling, perhaps a MSW, though not necessarily. They will often employ the same sort of techniques as psychologists.

4. Therapist - See all of the above! Usually a generic term for a professional offering some form of psychological support to a client. Most often refers to 2 and 3 above, but can in some cases refer to 1 as well.

Good luck,

d.