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For solicitors new to instructing mental health experts, the question often arises: should I instruct a psychiatrist or a psychologist? The answer depends on the issues in your case. Psychiatrists and psychologists have different qualifications, registration bodies and areas of expertise. Understanding the distinction is essential to selecting the right expert and ensuring the court accepts their evidence.
Psychiatry and psychology: the divide
Psychiatrists are doctors. They have completed medical school, followed by specialist postgraduate training in psychiatry. They are registered with the General Medical Council (GMC) on the Medical Register and, for specialist work, on the Specialist Register in psychiatry.
Psychologists are not doctors. They have completed a university degree in psychology, followed by a specialist qualification (such as a doctorate in clinical psychology). They are registered with the Health and Care Professions Council (HCPC) as practitioner psychologists.
This distinction has legal and practical consequences.
Psychiatrist: qualifications and GMC registration
A psychiatrist holds a medical degree (MBBS, BM or equivalent) and has completed postgraduate training in psychiatry, typically 5–6 years after medical school. They may hold a specialist qualification such as MRCPsych (Member of the Royal College of Psychiatrists) or, at senior levels, FRCPsych (Fellow).
Registration with the GMC is mandatory before a psychiatrist can practice. You can verify this via the GMC register (www.gmc-uk.org ). For medico-legal work, check that the psychiatrist is on the Specialist Register in the relevant subspecialty (general psychiatry, forensic, perinatal, etc.).
A psychiatrist’s registration may also show restrictions if they are under fitness-to-practise investigation by the GMC, or if previous complaints have led to conditions on their practice.
Key advantage: As a doctor, a psychiatrist can diagnose and prescribe medication. This is particularly relevant in cases where medical diagnosis and psychiatric pharmacology are central (e.g. whether the claimant has bipolar disorder or unipolar depression, and whether a particular antidepressant was appropriate).
Psychologist: qualifications and HCPC registration
A clinical psychologist holds a degree in psychology, followed by a doctorate in clinical psychology (often a 3-year course approved by the British Psychological Society). They are trained in psychological assessment, psychotherapy and research methodology.
A psychologist is registered with the HCPC (www.hcpc-uk.org ) as a practitioner psychologist. The HCPC register can be searched by name or registration number.
Some psychologists hold additional qualifications such as a diploma in forensic psychology, or post-doctoral specialisation in neuropsychology. These further qualifications are noted in their CV and often disclosed in expert reports.
Key advantage: Psychologists are trained extensively in psychological testing and assessment. Psychometric tests (standardised questionnaires measuring personality, cognition, memory, mood and behaviour) are administered and interpreted by psychologists. This is a core skill of the profession.
What each expert can assess
Psychiatrist addresses: diagnosis (depression, bipolar, schizophrenia, PTSD); presence of condition at particular time; medication (appropriateness, side effects, compliance); risk assessment (suicide, harm, relapse); prognosis; capacity assessment.
Psychologist addresses: psychological assessment using questionnaires and tests; cognitive assessment (memory, attention, executive function); psychological formulation; trauma assessment; fitness for duty. Psychologists cannot prescribe medication but recommend psychological treatment (CBT, psychotherapy).
When to instruct each
Instruct a psychiatrist alone if:
- Diagnosis of mental illness is the core issue (is the claimant depressed, or does she have bipolar disorder?).
- The case involves medication: what was prescribed, was it appropriate, did it cause side effects?
- Risk assessment of suicide or harm is central (criminal case, duty of care claim).
- The claimant’s capacity to make a decision (medical, financial, legal) is the question.
Example: A clinical negligence claim where the claimant alleges a GP misdiagnosed her depressive illness, leading to incorrect treatment and harm. A psychiatrist’s evidence on diagnosis and appropriate management is needed.
Instruct a psychologist alone if:
- Cognitive assessment is the primary issue (does the claimant have brain damage or dementia affecting memory or thinking?).
- Psychological trauma and PTSD are the focus, and detailed psychological assessment is required.
- The evidence turns on psychological factors rather than psychiatric diagnosis (e.g. occupational stress, fitness for work).
Example: A personal injury case where the claimant reports memory problems after a head injury. A neuropsychologist can administer objective tests of memory and cognition to determine whether deficits exist and their severity.
Instruct both a psychiatrist and a psychologist if:
- The case is complex, involving both psychiatric diagnosis and psychological assessment.
- Mental health treatment history includes both medication (psychiatrist’s domain) and structured psychotherapy (psychologist’s domain).
- Capacity assessment is required, combining psychiatric, psychological and functional elements.
Example: A complex family care case where a parent has bipolar disorder (psychiatric issue) but also presents with significant trauma symptoms (psychological). Both experts’ perspectives strengthen the assessment.
Neuropsychology
Neuropsychology is a psychological specialism assessing brain function and behaviour using cognitive tests (memory, attention, language, executive function). Neuropsychologists work in brain injury cases, providing objective quantitative evidence of cognitive deficit using normative data. Registered with HCPC (not doctors), they assess whether brain injury is genuine, severity of deficit, and recovery prognosis—providing objective measurement versus psychiatrist’s clinical interview.
Choosing between the two
Ask: What is the core question? Diagnosis → Psychiatrist. Psychological trauma severity and testing → Psychologist. Cognitive damage → Neuropsychologist. Combination → Both. Verify registration: Psychiatrist (GMC Specialist Register); Psychologist (HCPC register). Courts often order single joint expert; if both needed, argue for permission before court directs otherwise.
Working with both experts
If instructing both, ensure clear roles: Psychiatrist (diagnosis, treatment, medication, prognosis); Psychologist (psychological assessment, trauma, cognition). Both should address the same court questions; disagreements should be explained. Complementary reports strengthen evidence.
Key points
- Psychiatrists are doctors, registered with the GMC; they diagnose mental illness and prescribe medication.
- Psychologists are not doctors, registered with the HCPC; they specialize in psychological assessment and psychometric testing.
- Instruct a psychiatrist for diagnosis, medication and risk assessment; a psychologist for detailed psychological and trauma assessment, or cognitive testing.
- Neuropsychologists, a specialism of clinical psychology, provide objective testing of cognitive function in brain injury cases.
- Verify registration before instructing: GMC Specialist Register for psychiatrists, HCPC register for psychologists.
- In complex cases, both may be necessary, with complementary roles.
Related: Find a medico-legal expert