General Adult Psychiatry – Expert Witness

Introduction

General Adult Psychiatry focuses on the diagnosis and treatment of mental disorders in adults aged 18 to 65. Conditions commonly encountered include depression, bipolar disorder, schizophrenia, anxiety and phobic disorders, obsessive–compulsive disorder (OCD), post-traumatic stress disorder (PTSD), personality disorder, somatoform disorder, and eating disorders such as anorexia nervosa, bulimia nervosa, ARFID (Avoidant/Restrictive Food Intake Disorder) and binge-eating disorder. General adult psychiatrists are medically qualified doctors—typically MBBS, MRCPsych, or equivalent—and often hold additional postgraduate qualifications, for example, MSc in Eating Disorders or Cardiff University Bond Solon (CUBS) Expert Witness Certificates. Many are approved clinicians under Section 12 of the Mental Health Act 1983, experienced in assessing detained patients and those under the Mental Capacity Act 2005 or Deprivation of Liberty Safeguards (DoLS).

In legal proceedings, the psychiatrist’s duty is to the court, not to the party instructing them. Their work is governed by Civil Procedure Rules Part 35, Family Procedure Rules Part 25, and Criminal Procedure Rules Part 19, which require independence, objectivity, and transparency.

Typical Case Types

Criminal Court – Psychiatrists are instructed to assess mental state at the time of an offence, intent, capacity, or fitness to plead. Opinions may address diminished responsibility, insanity, or whether psychiatric illness influenced behaviour. They also advise on sentencing and the suitability of hospital treatment under the Mental Health Act.

Civil Court – Experts provide opinions on psychiatric injury following trauma, workplace stress, clinical negligence, or road traffic accidents. They assess causation, prognosis, and treatment needs for disorders such as PTSD or depression, and may evaluate mental capacity, occupational functioning, or disability under the Equality Act 2010.

Family Court – Psychiatrists assess parents or carers in care and safeguarding proceedings, determining how conditions such as bipolar disorder or personality disorder affect parenting capacity and risk. They may also advise on the adult’s capacity to make decisions concerning children or contact arrangements.

GMC Fitness to Practise – In regulatory proceedings, psychiatrists evaluate whether a doctor’s mental health condition—such as depression or substance dependence—impairs their ability to practise safely and whether recovery or supervision is appropriate.

Role of the Expert Witness

The psychiatrist’s role is to help the court understand the psychiatric aspects of a case. They interpret clinical evidence, translate medical terminology into plain English, and explain how conditions may influence behaviour, intent, or decision-making. They must act impartially, provide evidence within their competence, and base conclusions on sound medical reasoning. Experts use recognised diagnostic frameworks (ICD-10 or DSM-5) and, when appropriate, modern therapies such as Radically Open Dialectical Behaviour Therapy (RO-DBT) in the formulation of opinion.

Evidence and Reporting

Assessments involve a structured clinical interview, mental-state examination, review of medical and legal documents, and where appropriate, psychometric testing. Reports follow the prescribed court format: the expert’s credentials, instructions received, materials reviewed, findings, diagnosis, reasoning, and opinion on each question posed. Reports conclude with a Statement of Truth confirming compliance with the relevant procedural rules. In cases involving eating disorders, reports may also include nutritional status, BMI, and insight into the disorder’s psychological impact.

General adult psychiatrists may later respond to written questions, prepare joint statements, and give oral evidence under oath. Their contribution ensures that complex psychiatric evidence is clearly understood, enabling fair and informed judicial decisions.