First, all three can provide psychotherapy.  

A psychiatrist is a medical doctor and can prescribe medications for mental health conditions.  Often their practice is focused on medication management.  This service is covered by OHIP.

A psychologist holds a doctoral degree in the study of psychology.  Often, they do extensive testing to identify learning challenges and provide coping skills to clients to manage their emotional challenges. They can not prescribe medications.  This service has a limited coverage in an employee’s benefit package. 

A registered psychotherapist through exploration with a client of their thoughts, conscious feelings and reactions to situations brings awareness to the unconscious feeling patterns and dynamics at play.  From this awareness clients are then supported to build new ways of relating that allow them to live happier, healthier and more fulfilling lives.  Individuals must check their benefit package to see if their benefits provide coverage.