A psychotherapist is a professional who has the education and training to help individuals with a variety of presenting issues in the form of talk therapy. Psychotherapists have training in a wide range of therapeutic models and they often have experience working with a variety of issues, therefore they can offer a range of services. Many psychotherapists will offer a diverse amount of services including career counselling, grief counselling, addictions counselling, mental health counselling, and couples and family counselling.
A psychologist is a professional who can perform talk therapy much like a psychotherapist, but they can also conduct psychological and research testing.
A psychiatrist is a professional with a medical degree that can diagnose and prescribe medication to clients. Most often it is suggested if you work with a psychiatrist to also work with a psychotherapist for talk therapy.