Good question! Most people cannot distinguish between these disciplines. Regulatory bodies require each discipline to carefully represent themselves accurately.
First, let’s distinguish Psychiatry from counsellors, Social Workers or Psychologists. A Psychiatrist is a medical physician who is a specialist in the treatments and medicines for the mind. This is the only discipline (of those referenced here) that can prescribe medication. A General Practitioner/Physician/Doctor must make a referral for you to see a Psychiatrist. Only a Psychiatrist/GP/Physician or other medical Physician can prescribe medications. Their training largely follows a medical treatment model. As such, Psychiatry appointments are generally shorter in length, as they listen for symptoms that would give them cause to prescribe or adjust a medication. Your Pharmacist may know more about the drug in question so you should consult with that discipline if your Psychiatrist prescribes a medication.
There are relatively few Psychiatrists in Canada who see patients for a full hour for what is basically called “talk therapy” (involving no medication). In other words, the Hollywood version of a Psychiatrist is a bit misleading.
Now to confuse matters further, a Registered Psychiatric Nurse (who would have 2-4 years of academic training) may also be involved. The nurse monitors the symptoms and medication, offers some general talk therapy and works in concert (as a team member) with the Psychiatrist in a public practice setting (hospital or outpatient clinic).
Wait times are generally several months, though most times your Physician may have already started some pharmaceutical intervention for the Psychiatrist to adjust.
This leaves the non-medical/Pharmacological disciplines of Psychology, Social Work and generic “Counsellor”. In Saskatchewan, anyone can use the title of counsellor, therapist, mental health worker or a host of other labels. No training, licensing, or regulation is required. Occasionally you may see an allied degree (like a nurse or teacher) use the title of counsellor and represent a degree other than Social Work or Psychology. It is generally a good idea to look carefully into these services. The greatest issue (besides the obvious) is that they may not be accountable to any regulating body if you were to have a claim against them. In addition, the counsellor may not be insured at all, or their insurance may be very limited (and prohibitive). This is not to say they are not good at what they do. Some people with little to no training or allied training have a gift.