§ Lord Lucasasked Her Majesty's Government:
In the context of the draft Mental Health Bill, what evidence they have of the accuracy of predictions of violent behaviour (or the absence of it) by psychiatrists. [HL5313]
§ Lord Falconer of ThorotonResearch studies have been conducted on the relative accuracy of clinical opinion (i.e. the judgments made by clinical professionals such as psychiatrists and psychologists) in the assessment of violence (including sexual offending) in relation to actuarial or statistical risk prediction tools. The evidence from these studies indicates that statistically based risk prediction tools are more accurate in their predictions than clinical judgment alone. For example, a study by Bonta, Hanson and Law in North America indicated that actuarial risk assessments might be up to three times more accurate than predictions based on only clinical judgment.
More recently there has been a move towards developing risk assessment processes which combine the use of actuarial tools and structured clinical judgment to guide the decision-making process regarding risk of serious offending. Recent international research indicates that this is more effective in prediction than either actuarial tools or clinical judgment, taken on their own.
98WAThe assessment process for dangerousness and severe personality disorder, currently being piloted at HM Prison Whitemoor, follows best practice by using a combination of actuarial tools and structured clinical judgment to inform the overall assessment of risk for future violent and sexual offending.
The overall accuracy of this process is currently being evaluated by a group of independent researchers.
§ Lord Lucasasked Her Majesty's Government:
In the context of the Mental Health Bill, what proportion of people who under current legislation would fail the treatability test but who might be detained under the terms of the draft Bill, and who have been convicted of a serious offence against the person, have been the subject of a verdict of diminished responsibility in respect of that conviction. [HL5315]
§ Lord Falconer of ThorotonThis question cannot be answered without disproportionate cost. There is no central record of diminished responsibility pleas on grounds of mental disorder; nor of those which fail by reason of untreatability.
Forecasts derived from the Office for National Statistics Psychiatric Morbidity Survey of Prisoners indicate that 124 persons per annum could fail to be treated under Clause 6 of the Bill as being at substantial risk of causing serious harm to other persons due to a severe personality disorder. Members of this group could fall outside the Mental Health Act 1983 as being untreatable.
Central statistical databases do not hold information on the criminal convictions of all people admitted under the 1983 Act, other than for persons given hospital orders by the courts. It is therefore not possible to offer a breakdown of disposals of offenders with reference to treatability or diminished responsibility.