Who Does What? Psychiatrist, Psychologist, Neuropsychologist

Psychiatrist vs. Psychologist: Definitions and Training

A psychiatrist is a medical doctor specializing in mental health. After completing a medical degree, they complete a 4- to 5-year residency in psychiatry, which includes training in pharmacology, neuroscience, psychopathology, and internal medicine (Royal College of Physicians and Surgeons of Canada, 2024).

A psychologist holds a doctoral degree in psychology (Ph.D., Psy.D.) and receives advanced training in psychological assessment, psychometrics, cognitive neuroscience, human development, and psychotherapy—but is not a medical doctor (APA, 2021; OPQ, 2024).

This difference in training shapes the intervention tools, the scope of diagnostic authority, and the types of treatments each professional provides.

Key Differences in Terms of Interventions

A psychiatrist, as a medical doctor, can:

• make a medical diagnosis according to the DSM-5-TR (American Psychiatric Association, 2022);

• prescribe psychotropic medications;

• recommend hospitalization;

• order medical tests (EEG, MRI, bloodwork).

A psychologist does not prescribe medication. Their interventions rely on:

• psychotherapy;

• psychological evaluation;

• psychometric testing;

• interventions targeting emotions, thoughts, behaviors, and relationships (OPQ, 2023).

Therapeutic Approach: Complementary Perspectives

Psychologists use a variety of research-based therapeutic approaches: CBT, psychodynamic therapy, systemic approaches, humanistic therapies, and others (APA, 2006).

Psychiatrists may also provide psychotherapy, but their work is more often focused on severe mental disorders that require medical or pharmacological stabilization (Canadian Psychiatric Association, 2019–2024).

Psychological Diagnosis in Quebec: A Reserved Activity

Since the adoption of Bill 21, psychologists in Quebec have the legal authority to make a psychological diagnosis, specifically:

• for mental disorders;

• for neuropsychological disorders;

• as part of standardized clinical assessments (OPQ, 2023).

A psychological diagnosis is based on:

• a comprehensive clinical interview;

• analysis of emotional, cognitive, behavioral, and relational functioning;

• validated psychometric tools;

• a contextualized clinical formulation.

It is not a medical diagnosis, but a diagnosis recognized in clinical, educational, and organizational contexts as part of the psychologist’s scope of practice.

The Role of Neuropsychologists: Essential Expertise

Neuropsychologists are psychologists with specialized expertise in evaluating higher-order brain functions, including:

• attention, memory, and executive functioning;

• language, perception, and processing speed;

• the cognitive impacts of neurological and psychiatric conditions.

Their training includes advanced knowledge in neuroscience, cognition, standardized testing methodology, and statistical analysis (Lezak et al., 2012; Strauss et al., 2006).

What Neuropsychologists Can Diagnose

Under Bill 21, they may provide neuropsychological diagnoses, such as:

• ADHD;

• learning disorders;

• giftedness or intellectual disability;

• mild or major neurocognitive disorders;

• post-stroke, traumatic brain injury, or neurological cognitive profiles.

They play a key role in:

• academic or workplace accommodations;

• multidisciplinary treatment planning;

• return-to-work assessments;

• evaluating functioning in complex clinical situations.

The Psychotherapy Act in Quebec (Bill 21)

It is essential to understand the Psychotherapy Act, which strictly regulates who may provide psychotherapy in Quebec.

What the Law States

Psychotherapy is a reserved activity, defined as a psychological treatment aimed at:

• modifying thoughts, emotions, or behaviors;

• improving psychological health, functioning, or adaptation;

• treating a mental disorder, personality disorder, or behavioral disorder.

According to Bill 21 (Government of Quebec, 2012), only the following may legally provide psychotherapy:

• psychologists,

• physicians,

• and professionals who hold a psychotherapist’s permit (e.g., social workers, occupational therapists, nurses, sexologists, etc.).

What Psychotherapy Is Not

The Act distinguishes psychotherapy from:

• supportive counselling;

• helping relationships;

• psychosocial accompaniment;

• psychoeducation;

• prevention;

• coaching.

These activities may be offered by other professionals, but not psychotherapy, which requires advanced, supervised training and a recognized permit.

The Biopsychosocial Model: Two Perspectives, One Common Goal

Psychiatry relies on the biomedical / biopsychosocial model (Engel, 1977), integrating:

• biological factors (neurochemistry, genetics);

• psychological factors;

• social factors.

Psychology focuses on:

• mental and behavioral processes;

• emotional patterns;

• relational dynamics;

• developmental and personal history.

  
  

Both disciplines are grounded in strong scientific literature (Kazdin, 2017; Insel & Cuthbert, 2015).

When to Consult Whom?

Consult a psychologist if you experience:

• anxiety, stress, grief, relational difficulties;

• mild to moderate symptoms;

• a desire to understand your emotions or improve functioning;

• a need for psychological or psychometric assessment.

Consult a neuropsychologist if you experience:

• difficulties with attention, memory, or organization;

• suspected ADHD, autism spectrum disorder, intellectual disability, or giftedness;

• cognitive impacts following trauma or illness;

• persistent academic challenges.

Consult a psychiatrist if you experience:

• severe symptoms (major depression, bipolar disorder, psychosis);

• need for medication;

• symptoms that persist despite psychotherapy.

Why These Differences Matter: Complementary Approaches

The distinction between psychiatry and psychology is not hierarchical, but complementary:

• The psychiatrist’s medical model addresses situations where brain biology or neurochemical/physiological imbalances affect mental health, offering somatic treatments when necessary.

• The psychologist’s model explores lived experience, emotions, thoughts, trauma, and social or family dynamics—essential components of well-being, resilience, and personal development.

This complementarity is recognized by major clinical and professional organizations: both types of professionals may diagnose, evaluate, and treat, and often collaborate for comprehensive care.

What Science and Professional Associations Emphasize — And the Limits

Psychiatry is grounded in the biomedical model and neurobiological evidence: psychiatrists are trained to assess how biological, neurological, or genetic factors influence mental health.

Clinical psychology relies on methods derived from the social and behavioral sciences; psychologists use psychometric tests to assess cognitive functions, personality traits, and disorders. This psychological evaluation—distinct from medical evaluation—is one of psychology’s strengths.

Both approaches contribute meaningfully to reducing psychological suffering.

Often, integrated care—combining psychotherapy, medical follow-up, medication when necessary, and psychosocial support—is ideal.

However, limits exist:

• Some complex disorders require both biological and psychological treatments;

• Other issues (anxiety, stress, trauma, existential distress) may not require medication but benefit from long-term psychotherapeutic support.

What This Means for You (as a Patient, Clinician, or Professional)

As a patient, you should be informed about the training and competencies of the professional you are consulting. If it is a psychologist, ensure they are registered with the provincial regulatory body (e.g., the Ordre des psychologues du Québec).

Choose the appropriate professional based on the severity, complexity, and nature of symptoms (emotional, behavioral, biological) and your goals (crisis support, psychotherapy, medication, long-term therapy, evaluation, etc.).

As a health professional, recognizing the complementary nature of these approaches can support better referrals and more integrated care—especially in complex mental health situations.

Conclusion: Not in Opposition, but in Partnership

Psychologists, psychiatrists, and neuropsychologists all offer distinct yet complementary contributions:

• The psychiatrist addresses biological and medical aspects;

• The psychologist explores lived experience, internal patterns, emotions, and psychological functioning;

• The neuropsychologist clarifies cognitive mechanisms and neuropsychological diagnoses.

According to the research, the most effective care is often integrated, combining psychotherapy, medical follow-up, cognitive evaluation, and psychosocial interventions (Cuijpers et al., 2020; NICE, 2022).

References

American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev.; DSM-5-TR).

American Psychological Association. (2006). Evidence-based practice in psychology. American Psychologist, 61(4), 271–285.

American Psychological Association. (2014). Standards for educational and psychological testing.

American Psychological Association. (2021). Clinical practice guideline for the treatment of depression.

Canadian Psychiatric Association. (2019–2024). Clinical practice guidelines.

Collège royal des médecins et chirurgiens du Canada. (2024). Programme de résidence en psychiatrie.

Cuijpers, P., Noma, H., Karyotaki, E., Cipriani, A., & Furukawa, T. A. (2020). Combining psychotherapy and medication treatments for depression: A meta-analysis. World Psychiatry, 19(3), 290–299.

Engel, G. L. (1977). The need for a new medical model: A challenge for biomedicine. Science, 196(4286), 129–136.

Fournier, J. C., et al. (2010). Antidepressant drug effects and depression severity. JAMA, 303(1), 47–53.

Gouvernement du Québec. (2012). Loi modifiant le Code des professions et d’autres dispositions dans le domaine de la santé mentale et des relations humaines (Loi 21).

Insel, T. R., & Cuthbert, B. N. (2015). Brain disorders? Precisely. Science, 348(6234), 499–500.

Kazdin, A. E. (2017). Evidence-based psychotherapies: Current status and future research directions. Annual Review of Clinical Psychology, 13, 1–28.

Lezak, M. D., Howieson, D. B., Bigler, E. D., & Tranel, D. (2012). Neuropsychological assessment (5th ed.). Oxford University Press.

National Institute for Health and Care Excellence. (2022). Depression in adults: Treatment and management.

Ordre des psychologues du Québec. (2023). L’évaluation et le diagnostic psychologique : lignes directrices professionnelles.

Ordre des psychologues du Québec. (2024). Normes de formation doctorale.

Strauss, E., Sherman, E. M., & Spreen, O. (2006). A compendium of neuropsychological tests (3rd ed.). Oxford University Press.