Mental disorder does not automatically reduce a sentence, but the court must always consider it, and good psychiatric evidence often decides whether it makes a difference. A significant proportion of defendants in the criminal courts have a mental disorder, developmental condition or neurological impairment. For many, the most important stage at which their condition is examined is not trial but sentence.

At sentence, psychiatric evidence can bear on how blameworthy the offender was, what type of sentence is appropriate, whether the offender is “dangerous” in the statutory sense, and whether a hospital-based disposal under the Mental Health Act 1983 would better serve both the offender and the public. This page sets out the framework the courts in England and Wales apply, and where the expert psychiatrist fits within it.

The Sentencing Council guideline

Since 1 October 2020, courts in England and Wales have applied the Sentencing Council’s overarching guideline on sentencing offenders with mental disorders, developmental disorders, or neurological impairments. It applies to adults who had a relevant condition at the time of the offence, at the time of sentence, or both – for example schizophrenia, depression, PTSD, autism, intellectual disability, acquired brain injury or dementia.

Its central principles are:

Always considered, not always decisive. The court must consider the condition, but it will not necessarily affect the sentence.
Individual, not diagnostic. The level of impairment varies widely between people with the same diagnosis, so the approach must focus on the individual and the issues in the case.
Caution about assumptions. Many conditions are not easily recognised, may fluctuate, may be undiagnosed or undisclosed, and often co-exist with other disorders or with substance misuse that can mask them. No adverse inference should automatically be drawn from an absence of previous diagnosis.
A formal diagnosis is not always needed. Where one is, a report from a suitably qualified expert is required.
Equality considerations. Courts should be alert to cultural, ethnic and gender factors, and to the particular mental health needs of women, people from ethnic minority backgrounds, refugees and asylum seekers.

Where an offender is or appears to be mentally disordered, the court must obtain and consider a medical report before passing a discretionary custodial sentence, unless it considers one unnecessary (section 232 of the Sentencing Code). That report must come from a doctor approved under section 12 of the Mental Health Act 1983. The court must also consider the likely effect of custody on the offender’s condition and on any available treatment.

Culpability: the causal link

Culpability may be reduced only where there is a sufficient connection between the condition and the offending. The court first assesses culpability under the relevant offence-specific guideline, then asks whether the disorder reduced it – significantly, partly, or not at all.

The guideline suggests a starting point. At the time of the offence, did the condition impair the offender’s ability to:

exercise appropriate judgement;
make rational choices;
understand the nature and consequences of their actions?

It also asks whether the condition caused disinhibited behaviour, and directs attention to three recurring issues:

Medication. Was non-adherence wilful, or did it stem from a lack of insight caused by the illness itself?
“Self-medication”. Where alcohol or illicit drugs worsened the condition, how far did the offender know they would?
Insight. Some insight does not automatically increase culpability; it is a matter of degree.

These are precisely the questions on which a forensic psychiatrist can give the court structured, evidence-based assistance. Where the condition is unconnected to the offence, it may still be relevant as personal mitigation, to the choice of sentence, and to the impact of custody, which can weigh more heavily on some disorders and worsen them.

Where the expert’s role ends

The judge, not the expert, decides culpability. The guideline is explicit: expert evidence must always be considered and is often very valuable, but the court is not bound by it if there are compelling reasons to depart from it, and must give reasons when it does.

How far a psychiatrist should go towards the ultimate question is a live debate in the profession:

Hallett (2020) argues that the determination of culpability belongs to the court. The expert can and should address the clinical factors that bear on it – symptoms, capacity, insight, decision-making, substance use, help-seeking – but should resist expressing a view on the level of culpability itself.
Rix (2026) takes the contrasting position in the specific context of manslaughter by reason of diminished responsibility. The sentencing guideline for that offence requires the judge to assess the offender’s level of retained responsibility (high, medium or lower). Following the sentencing remarks in R v Worby (Luton Crown Court, December 2025), Rix argues that retained responsibility is a proper matter for expert psychiatric evidence.

In practice, the most useful report does the clinical-legal translation carefully. It explains what the offender’s mental state was, how it affected their functioning at the material time, and how that maps onto the questions the guideline poses, while being transparent about where clinical opinion ends and judicial evaluation begins.

The partial defence itself is explained on our diminished responsibility page.

Dangerousness

Where an offender is convicted of a specified violent, sexual or terrorism offence, the court must decide whether they are “dangerous”: whether there is a significant risk to members of the public of serious harm from the commission of further specified offences. A finding of dangerousness opens the way to an extended sentence or, in the most serious cases, a life sentence.

The assessment is for the court, but it often turns on psychiatric evidence: the nature of any disorder and its relationship to past offending, how far risk depends on treatment, insight and substance use, and whether risk is better managed in hospital or under a prison sentence. A report that addresses risk should explain the method used, including any structured professional judgement instrument, and distinguish the likelihood of reoffending from the likelihood of serious harm.

Choosing the right disposal

Psychiatric evidence is often decisive in determining which type of sentence best meets the purposes of sentencing. The main options are:

Disposal	What it does	Key psychiatric questions
Community order with a mental health treatment requirement	Treatment in the community, as an alternative to short or moderate custody	Does the condition require and respond to treatment? Has treatment been arranged? Is the offender willing to comply, as the requirement demands?
Hospital order (s.37 MHA 1983)	Detention in hospital for treatment, with no penal element	Are the statutory criteria met at the date of sentence? Is appropriate treatment available, and a bed within 28 days?
Restriction order (s.41 MHA 1983)	Added to a hospital order; leave, transfer and discharge come under Ministry of Justice control, without limit of time	Is it necessary to protect the public from serious harm?
Hospital and limitation direction (s.45A MHA 1983)	A prison sentence, served initially in hospital (a “hybrid order”)	Is a penal element appropriate? Which release regime better protects the public?

The guideline stresses that no order should be assumed to be better, or more protective, than another. The court must weigh the offender’s behaviour when unwell, insight, history of compliance, how quickly risk can escalate, and the very different release and recall regimes that follow each order. Where treatment would be privately funded, the court must be satisfied that it is secure, specialist and sustainable.

The choice between a section 37/41 order and a section 45A direction is among the most consequential decisions in this field. The Court of Appeal gave guidance in R v Vowles [2015] EWCA Crim 45 and, after that guidance was misunderstood, clarified it in R v Edwards [2018] EWCA Crim 595. The first step is to consider whether a hospital order may be appropriate; if so, the judge should consider all the sentencing options, including a section 45A direction. A judge who makes a section 37/41 order must explain why a penal element is not appropriate.

Peay (2015) analysed the use of section 45A and warned that “partial culpability” is a fluid concept. It may be used to justify hybrid orders that allow more risk-averse release and recall thresholds, introducing a degree of incoherence into how mentally disordered offenders are sentenced. Clear expert evidence on both the clinical picture and the practical operation of each regime helps the court reason through that choice.

These disposals remain governed by the Mental Health Act 1983 as amended. The Mental Health Act 2025 will change parts of that framework, but its provisions are being brought into force in stages and most are not yet in force.

Objectivity and bias

An expert’s overriding duty is to the court, not to the party who instructs them. The Royal College of Psychiatrists’ guidance, CR193 (Responsibilities of psychiatrists who provide expert evidence to courts and tribunals, 2023), sets out the standards expected of psychiatrists in this role.

Sentencing evidence is particularly exposed to bias because psychiatric opinion leaves considerable room for the expression of personal values. Eastman and Rix (2022) note that much expert bias is unconscious and commonplace rather than deliberate. One important route to it is poor “clinico-legal mapping”: failing to keep the clinical description of mental state distinct from the legal test, and then relating one to the other transparently.

Good practice therefore includes reasoning that can be followed and tested, engaging with alternative explanations, separating what the evidence shows from what it suggests, and acknowledging the limits of the expertise offered.

What our sentencing reports cover

Sentencing reports are prepared by consultant forensic psychiatrists approved under section 12(2) of the Mental Health Act 1983, the approval required for a medical report under section 232 of the Sentencing Code. A report will typically address:

diagnosis, including neurodevelopmental conditions, co-morbidity and the role of substance use;
the offender’s mental state at the time of the offence and now;
the relationship, if any, between the condition and the offending, mapped to the questions in the Sentencing Council guideline;
medication adherence, insight and “self-medication”, where relevant;
the likely impact of custody on the condition and on access to treatment;
risk, including any bearing on dangerousness;
the suitability and practicality of each available disposal, including treatment arrangements, bed availability and release regimes;
communication needs, and how the offender can be helped to understand the sentence and any orders.

Reports comply with Part 19 of the Criminal Procedure Rules and the RCPsych guidance on expert evidence. Where a hospital disposal is in prospect, we say so early enough for a second medical opinion and a bed to be arranged before the sentencing hearing. A section 45A direction cannot be given unless at least one of the doctors gives oral evidence, so attendance at court should be planned for.

Psychiatric reports for sentencing