Psychologist, counsellor, social worker, and psychiatrist. What do they all mean? Who should I see for therapy? Well, it depends on the province or state that you live in. For myself, my regulatory body has authorized different levels of intervention from state to state. For example, when I lived in Maryland, I had the authority, if needed, to hospitalize a client if I was concerned about their mental state. In Alberta, that role was only for psychiatrists.
In British Columbia, this is what I have gathered thus far. Feel free to email me if I've mistaken anything here. All of these clinicians can call themselves a "therapist" or "counsellor" and conduct therapy.
Psychologists: have a graduate level degree but are not MD's (cannot prescribe medication), have trained in assessment, diagnosis and treatment of mental disorders, and are able to administer various psychology tests. They are regulated by the British Columbia Psychological Association.
Counsellor: this term can be used by anyone and is not regulated. It generally means that a person does some form of talk therapy. Some counsellors in B.C. are Registered Clinical Counsellors. This is a regulatory body that follows strict guidelines (A master's degree in a related field with strong clinical skills and experience).
Social Worker: Bachelor (BSW) or Master (MSW) level social work training. Programs vary but emphasis is on a combination of policy, activism, social justice, clinical care. Social workers that do therapy either do extra training to be a therapist or went to a program that specializes in clinical work (this was the case for me). Regulatory body is the B.C. College of Social Workers.
Psychiatrist: Is a medical doctor, have been through medical school and residency. They tend to train in a way that is more focused on a medical model of care, but some also train in talk therapy or behavior therapy. They can prescribe medication and do therapy. They are regulated by the College of Physicians and Surgeons.
In my opinion, as the client seeking therapy, it is most important that you find someone who is a good fit for you. It doesn't matter too much what their background is as long as you can do the work together. Of course, if you are looking for medication, it would be important to find a psychiatrist. And, if you have insurance coverage, find out which professional designation your insurance will reimburse for.