What is the difference between a psychiatrist and a psychologist?
Many people are unsure of the difference between a psychiatrist and a psychologist. The prefix “psych” comes from the ancient Greek psykhē, via the Latin psyche, which has evolved to mean mind.
A psychiatrist is a medical doctor who specialises in the assessment, diagnosis and treatment of mental disorders. Although some psychiatrists use talking therapies as part of their practice, they are in a minority in the UK. Psychiatrists more commonly use psychotropic medication when treating mental disorders, but psychiatrists will often make referrals to psychologists, psychotherapists and talking therapists when psychological therapy or talking therapy is required. Although prescribing is one role that sets psychiatrists aside from psychologists, it is not the only distinction. Whilst some psychologists, and usually clinical psychologists, diagnose, diagnosis is another function which is most often fulfilled by psychiatrists.
Psychiatrists, as medical practitioners, have other responsibilities too. Where there is any doubt about the origin (aetiology) of mental health symptoms, a psychiatrist is trained to recognise when mental and behavioural symptoms may instead be the result of physical conditions such as infection, hormonal imbalances (such as thyroid disease), cancer, and lesions of the central nervous system. In multidisciplinary management of mental disorders, psychiatrists often fulfil the role of clinical lead for a patient’s care; however, there are instances where another team member, and often a psychologist, will take on this responsibility.
What training is involved in becoming a psychologist?
Psychologists’ training is no less extensive. Their training depends on their field of psychology. There are various psychological disciplines but the ones which arise most often in expert witness practice are clinical, forensic and educational psychology. All psychologists begin their education with a three-year bachelor’s degree in psychology. At this stage, the study is broad. In contrast to medical students, many psychology undergraduates do not go on to practise as a psychologist. The competition for a career in psychology is intense. Many psychology graduates will become assistant psychologists before they are able to enter professional training, which leads to a doctorate degree in their chosen field. For example, a psychologist who trains to become a clinical psychologist will acquire the degree of DClinPsy (Doctorate in Clinical Psychology).
The fact that psychologists use the title “Dr” as conferred by their doctorate degree can lead to some confusion as many people automatically equate “Dr” to mean a medical doctor. In fact, medical doctors such as psychiatrists use the title as an honorary title because their degree is not held at a doctorate level (e.g. PhD, ForenPsyD, DClinPsy etc).
Professional witness definition: how to decide which professional witness you require
Deciding which expert you need may not always be straightforward. In some proceedings, the need for a psychiatric assessment will be clear. For example, in civil proceedings, a psychiatrist will be needed if you need to demonstrate that psychiatric harm has occurred and whether that harm has been caused by the index event, or whether the index event contributed to that harm. Similarly, in criminal proceedings, the availability of diminished responsibility as a defence to murder must be addressed by a psychiatrist rather than a psychologist. In other instances, the need for a psychologist over a psychiatrist will be equally as clear. For example, structured assessments of personality are almost always conducted by psychologists rather than psychiatrists. Other examples include the assessment of intelligence using scales such as WAIS-IV (Wechsler Adult Intelligence Scale) to measure cognitive ability in adults, WISC-V (Wechsler Intelligence Scale for Children) to measure cognitive ability in children, and the WASI-II (Wechsler Abbreviated Scale of Intelligence).
However, in a good proportion of cases, either expert could complete the assessment albeit with different assessment approaches. For example, both experts can comment on issues such as trauma, neurodevelopment and adverse childhood experiences, but a psychologist is likely to be better suited to commenting on attachment styles whereas a psychiatrist would be the more appropriate expert to form an opinion as to whether the diagnostic criteria for post-traumatic stress disorder are fulfilled.
How do psychiatrist expert witnesses undertake their assessments and compile their written expert evidence?
Psychiatrists will need to see the bundle from the relevant legal proceedings. Usually, psychiatrists will wish to see everything but there may be instances where this would be inappropriate or unnecessary. For example, in complicated fraud proceedings, the expert would not need to see the several thousand pages of financial transactions etc to form their expert opinion. Although medical records will always be requested, we recognise that in some cases they may be unobtainable.
After the psychiatrist has reviewed the bundle and other documents (including the medical records and letter of instruction), the psychiatrist will almost always need to interview the person to whom the proceedings relate. At interview, the psychiatrist will take a full history from the subject including their personal history, family history, relationship history, social history, past medical history, past psychiatric history, drug and alcohol history, forensic/offending history, and details about the index events (in civil and family law) or the index offence (in criminal law). There follows an assessment of the subject’s mental state which will establish a description of the subject’s appearance and behaviour, speech, mood and perception (e.g. evidence of hallucinations), thoughts (e.g. obsessional and delusional thoughts), cognition (e.g. memory and orientation) and their insight (what they understand about their mental health).
After the assessment, the psychiatrist will write a report in which they will formulate opinions and recommendations.