Mental Health and the Expert Witness World: Why it Matters More Than Ever at the Centre of Modern Clinical Negligence

January 8, 2026

Mental health is rarely a peripheral issue in medico-legal work. Increasingly, it sits at the heart of the many complex clinical negligence and personal injury claims, shaping questions of capacity, liability, risk, and recovery, and determining what care, supervision and support may be required not just in the short term, but for years, or even a lifetime.

Frontline Clinical Insight Meets Medico-Legal Expertise

At Bush & Co, we see this intersection of mental health and law daily. Our associate mental health experts bring decades of frontline clinical experience and medico-legal expertise, working across some of the most sensitive cases in the system. From emergency department risk assessments and liaison psychiatry, to secure in-patient care, community mental health failures and family court disputes over capacity, our experts are instructed where clarity, balance and sound clinical reasoning are essential.

Capacity, Autonomy and Psychiatric Injury

Capacity is one such area where the stakes could not be higher. Whether the issue is litigation capacity, testamentary capacity, or decision-making around health and welfare, the outcome of an expert report can fundamentally alter a person’s autonomy, rights and future. Clear, evidence-based opinion, grounded in a deep understanding of the clinical issues involved, can be the difference between prolonged dispute and resolution.

The same is true of psychiatric injury, which so often follows personal injury, workplace incidents or traumatic medical events. In these cases, diagnosis alone is often only the starting point; the long-term implications for employment, care needs and quality of life are central to quantum, and must be addressed with care and foresight if the right outcome is to be achieved.

High-Risk Clinical Negligence and Restrictive Practices

Mental health work also frequently occupies the most difficult end of clinical negligence: high-risk, time-pressured environments where decisions are made under strain. This is an area our mental health experts are watching closely. Sian Cooper, is an advanced nurse practitioner specialising in acute mental health, tribunals and forensic mental health services. As both a clinician and a Bush & Co expert witness, Sian commented:

“Acute presentations in A&E, the use of liaison psychiatry services, and care within forensic settings all raise complex questions about risk assessment, documentation, escalation and lawful decision-making. Cases may turn on whether restrictive practices such as restraint, seclusion or segregation were clinically lawful, justified and proportionate. These cases require mental health experts who understand not only policy and guidance, but the operational realities of mental health care, and what happens when systems fail.

“What is becoming increasingly clear is that this area of clinical practice and medico legal work is evolving. Recent case law and national scrutiny are signalling a shift in how mental health care, particularly in restrictive practices, is viewed through a human rights lens. The recent judgment in the case of Fuad Awale has drawn attention to the legal consequences of prolonged segregation and its psychological impact.”

Legislative Reform and a Shifting Legal Landscape

Alongside this, mental health law itself is in a period of reform. The Mental Health Bill, which received by Royal Assent on 18th December 2025 and became the Mental Health Act 2025, aims to modernise mental health legislation, providing patients with greater choice, autonomy and rights. These changes will be implemented over the next five years and for solicitors and expert witnesses alike, this means cases will be increasingly assessed against a backdrop of change; where historical practice may be judged by emerging clinical and ethical standards.

The Inseparability of Mental and Physical Health

Another recurring theme in our work is the inseparability of mental and physical health. Claimants recovering from brain injury, spinal trauma or chronic pain frequently experience psychiatric sequelae, with pre-existing conditions and vulnerabilities amplified by injury, uncertainty and the litigation process itself. Effective expert evidence must therefore be genuinely holistic, integrating psychiatric and psychological needs into assessments of liability, causation and quantum, rather than treating them as peripheral or lesser needs.

Stephen Marks is a highly experienced mental health nurse and advanced clinical practitioner as well as lecturer and Bush & Co expert witness. Commenting on the importance of recognising both physical and psychological health, Stephen said:

“It is impossible to separate mental health from physical health, and when clinicians fail to see people holistically, outcomes are significantly worse. People living with severe and enduring mental illnesses, such as schizophrenia and bipolar affective disorder, are much more likely to experience multiple physical health co-morbidities, and die on average 20 years earlier than the general population. Suicide is a significant factor in this, but failure to recognise physical symptoms happens often in a phenomenon known as diagnostic overshadowing, whereby genuine symptoms are dismissed as part of someone’s mental illness.

“The Mental Capacity Act is poorly understood by many clinicians, who feel this is purely the responsibility of mental health staff. The reality is that all healthcare professionals need to have in-depth knowledge of the legislation as it most often applied when there is a decision to be made regarding someone’s physical health, and the causes are often organic in nature such as infection, delirium, or induced by medication. With an ever increasing focus on integrated healthcare it is imperative that all clinicians are able to holistically assess all aspects of a person’s health.”

Excellence in Expertise and Quality Assurance

It is in this complexity that the quality of expert evidence matters most. At Bush & Co, our focus on Excellence in Expertise means we do not simply supply experts for cases, we assure the instruction of ‘expert experts’. Every expert witness who joins us receives unrivalled training, mentorship and support, ensuring their clinical expertise is matched by a clear understanding of their legal duties, procedural requirements and strategic context. This allows them to operate autonomously whilst still maintaining medico-legal standards and responding to the Letter of Instruction.

Our reports are recognised for being analytically rigorous, balanced and court-ready, underpinned by one of the most experienced quality assurance teams in the sector, comprising former solicitors and seasoned experts who understand what scrutiny looks like at every stage.

We also believe expertise should be shared. Through CPD, insight events and collaborative work with solicitors, we contribute to a wider understanding of how mental health evidence is developing, and where future challenges are likely to emerge.

As Bush & Co approaches its 40th year, we continue to be trusted with the most sensitive and complex mental health cases, from liability through to quantum and capacity. In a landscape that is shifting clinically, legally and culturally, solicitors can be confident they are instructing expert witnesses who combine clinical depth, legal awareness and professional credibility – and most importantly, who understand not only where mental health law has been, but where it is going.