I am often asked about the difference between a psychologist and a psychiatrist or a social worker and a licensed counselor.  There are many different professionals who provide direct service to people seeking help from mental health professionals. The education, training and areas of expertise vary widely. This article will give a general explanation of the more prominent mental health professions, their educational and training backgrounds.
Psychologist (Ph.D.) – Doctorate of Philosophy, a clinical/research degree
The average length of a Ph.D. program is 6-7 years emphasizing psychological evaluations, theories and practice of psychotherapy, research and statistics, diagnosis and ethics, much more so than any other degree. Pre-internship training (practicum), internship and the completion of a dissertation are required for degree completion.  The differences between psychologists who graduated from a clinical program and those who graduated form a counseling program are minor. Clinical programs, which are greater in number, tend to focus more on serious mental illness such as depression, schizophrenia, anxiety, etc. Counseling programs tend to focus on change of life issues such as divorce, relationship problems, academic difficulties, etc.
Psychologist (Psy.D.) – Doctorate of Psychology, a professional degree
The Psy.D. was established in the late sixties and is more clinically oriented than the more traditional Ph.D. The average length of this degree program is 5-6 years. It requires more training and practicum experience instead of the research and statistic requirements of Ph.D. programs.  Most Psy.D. programs also require a dissertation, although some require an extensive research paper.  The degree focuses on psychological evaluations, theories and practice of psychotherapy, diagnosis and all forms of treatment delivery in a variety of clinical settings.
Social Worker (M.S.W.) – Master of Social Work
Social work programs generally last from 2-3 years. Degree attainment requires supervised clinical experience. Program emphasis is on psychotherapy and efforts to integrate people with available community resources.  Most social workers pursue careers as general psychotherapists, family therapists, case managers and/or EAP counselors.
Counselor/Therapist  (M.A., M.S.) – Master of Arts or Master of Science
The Master of Science is often a terminal degree meaning that the student plans to end their academic career with the Master’s degree, at which point they go on to become a general practitioner. The Master of Arts is a degree requirement necessary for admission to a doctorate program.  Both degrees are about 2 years in length, emphasize general psychotherapy techniques and require the completion of a thesis. There are few, if any, requirements for psychological assessments, theory and research.
Psychiatrist (M.D.) – Medical Degree
Psychiatrists begin their careers as general doctors and then complete a 3-4 year residency (training) in psychiatry. Residency training typically includes experience in medication management, diagnostic and crises evaluation in both inpatient and out patient settings.  Usually, psychiatrists receive no formal training in psychological assessment, research, or the practice and theory of psychotherapy.  Psychiatrists are the only mental health professionals that can prescribe medication and this is the mainstay of most who are in private practice.

Holly Houston, Ph.D.