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Review of the Research Literature on Serious Violent and Sexual Offenders - Research Findings

DescriptionThis review was undertaken to assist the work of The MacLean Committee on serious violent and sexual offenders.
Official Print Publication Date
Website Publication DateJune 27, 2000
Crime and Criminal Justice Research Findings No. 46Review of the Research Literature on Serious Violent and Sexual Offenders

Clare Connelly and Shanti Williamson, School of Law, University of Glasgow

This review was undertaken to assist the work of The MacLean Committee on serious violent and sexual offenders, by providing a review of current literature on how serious violent and sexual offenders and severe personality disordered offenders are treated and managed.

Main Findings

  • Provisions specifically designed to deal with offenders designated serious violent and/or sexual offenders exist in a number of countries.
  • These provisions provide for longer than normal, indeterminate or renewable sentences.
  • Although similar provisions are available across countries it is possible to divide jurisdictions into two models. Those that have adopted a more therapeutic and treatment orientated approach are grouped under the 'clinical model'. Many countries which did, historically adopt such a model now prioritise public safety and are grouped under the heading 'community protection model'. Within these headings there are variations and some countries, e.g., England and Wales bridge both models.
  • To comply with the applicable constitutional or human rights protections these provisions normally have appeal and review of detention provisions included.
  • Challenges in terms of constitutional or human rights breaches have clarified that detention of this type is 'lawful' even if the offender is not being 'treated' and its only purpose is public safety.
  • Offenders sentenced under these provisions are detained either in prison or hospital.
  • The place of detention tends to depend on whether the jurisdiction prioritises treatment or public protection.
  • In addition to detention some jurisdictions use castration as a form of 'treatment' for sexual offenders.
  • There is limited research and information that evaluates the effectiveness of these disposals and 'treatment'. This is in part due to the fact that many of these provisions are too new for any evaluations to have been carried out. The information that is available generally measures success in relation to the recidivism of offenders and provides mixed conclusions.


The main aim of the research was to provide a summary of current and recent UK and international literature on the sentencing of dangerous offenders and the subsequent management of these offenders, whether in hospital or prison settings, and upon release into the community. The key objectives of the research were to:

  • Review UK and international literature on dangerous offender legislation
  • Review any literature on reviewable and/or renewable sentences
  • Review any available literature on the effectiveness of dangerous offender legislation or reviewable sentences
  • Review the current and recent UK and international literature on the management of severe personality disordered offenders and offenders sentenced under dangerous offender legislation.

This research was conducted from 5 July until 30 September 1999. A literature search was conducted utilising available electronic, CD-ROM, and online databases. The literature search was conducted for references published in the English language or for those with an abstract in the English language. Literature published in languages other than English were excluded from the present review. Although this did not seriously affect the quality of the review, it does present a bias towards English speaking countries in the review of literature. Web sites of countries identified as having relevant legislation were consulted. Individuals with a local knowledge of their jurisdiction were contacted where possible.

Serious Violent and Sexual Offenders Legislation

Literature revealed a substantial amount of information on both the current and prior legislative provisions to deal with this group of offenders. Established and operational provisions were identified in the USA, Canada, Australia, New Zealand, The Netherlands, Germany, Switzerland, Denmark and England and Wales. Additional but limited information was collated on Belgium, Norway, Italy, Spain, Iceland, Finland, France, Hungary and Poland.

Shared approaches to dealing with serious violent and sexual offenders exist within and between jurisdictions. In those countries where sentencing laws are determined at state level e.g., USA and Australia, variations between some states are evident alongside a movement towards a unified approach that prioritises public safety. To facilitate examination of different countries a model approach is utilised. This focuses on the Public Protection Model and the Clinical Model.

The Community Protection Model

This model is found in the USA, Canada, Australia and New Zealand. The USA can be distinguished from the other jurisdictions as the indeterminate sentencing takes the form of civil commitment, which is applied after the completion of a prison sentence. It only applies to sexual offenders and the legislation of this type which exists in different states is known as sexual predator statutes. For non-sexual violent offenders the normal sentencing provisions e.g., '3-strikes' are available.

In Canada, Australia and New Zealand indeterminate sentencing, similar to the USA is available. Although this legislation also prioritises public protection and incorporates review mechanisms in respect of detention, there are some notable differences. The legislation in these countries does not make the same distinction between sexual and non-sexual violent offenders. Also, the decision on indeterminate sentencing is made at the point of disposal for the index offence and not at the completion of the prison sentence, as in the USA. Constitutional and Human Rights challenges to this legislation have highlighted that a system of regular review of detention is essential.

The Clinical or Therapeutic Model

The Netherlands, Germany, Switzerland and England and Wales have been described as having a more clinical approach to dangerous offenders, which is more orientated towards treatment rather than punishment and public protection. The TBS order in The Netherlands allows post-trial detention in a forensic mental hospital for offenders with partial or completely lacking responsibility. Treatment is provided in this setting. An offender can elect not to be assessed to receive such an order, which is made at the point of sentencing. If the offender chooses not to participate they will receive a normal prison disposal. Regular review procedures in respect of these orders are stringent.

Like the Netherlands, Germany provides hospital detention for the partially responsible offender. The decision to include an offender in such a regime, however, focuses on considerations of dangerousness and previous convictions rather than illness. Surgical castration is available in respect of sexual offenders and indeterminate civil commitment can be used for offenders who are dangerous and insane but this is rarely used.

In Switzerland preventative detention is available for offenders who evidence a deep-seated personality disorder and have committed a serious violent offence. Detention is aimed at preventing future similar offending. Regular review provisions are incorporated.

Those offenders committing the most serious offences in Denmark will receive a dangerous offender order if a risk of future offending is evident. The order, which is initially for a fixed period, is renewable. Serious sexual offenders are castrated in Denmark. Surgical castration has now been replaced by chemical castration combined with psychotherapy.

England and Wales has been described as part of the clinical model. This is due to the existence of disposals such as, the Hospital Order and Hospital and Limitation Direction, which are available to convicted offenders with mental disorder. Recent legislation, however, in the form of longer than normal sentences and current proposals for further change evidence a distinct shift towards the public protection model.

Shared Characteristics

All of these jurisdictions, despite having individual legislative provisions, do have shared characteristics. A large number of countries have introduced legislation following a high profile crime committed by a recently released offender with some history of serious offending.

The largest category of offenders in receipt of indeterminate sentencing or detention is sex offenders. The treatment of this group appears to be problematic and various approached have been adopted with limited success. A very large number of offenders in every jurisdiction have been described as suffering from personality disorders and often, severe personality disorders. It is not always clear from the literature, however, how the author defines this category.

There appears to continue to be a growth in the creation of new forms of indeterminate sentencing internationally. A movement away from an emphasis on treatment and rehabilitation towards prioritising public safety is obvious not only in the legislation, which is already in force, but that which is currently in the process of becoming law.

Evaluation of Effectiveness

There is limited literature available, which reflects on the effectiveness of these legislative provisions. That which does exist presents a mixture of results. The common trait in this literature is the approach adopted. The legislative provisions are either evaluated on the basis of how successful they are at reducing recidivism or alternatively, whether they comply with human rights or constitutional provisions.

The current public protection legislation has not been in existence for long enough to allow evaluations to have been conducted. The USA provisions, which are some of the earliest, only came into force for the first time in 1990. The majority of offenders detained under these provisions have, therefore, not yet been released.

Compliance with Human Rights Provisions

Each of the jurisdictions outlined are required to comply with the protections contained within their national equivalent of the European Convention on Human Rights. Scotland is no exception to this.

The position in the USA in this regard is outlined in the case Kansas v Hendricks. In this case, in 1997, the United States Supreme Court approved the constitutionality of Kansas' sexual predator statute. The Supreme Court's disposal of the constitutional issues raised can only be interpreted as providing approval for the viability of a model of community protection within a country and legal system strongly founded on the principles of liberty and due process.

In this decision and in those of the European Court of Human Rights the essential compliance criteria appear to be an absence of inhuman treatment or punishment, which may in Europe affect the lawfulness of compulsory castration, particularly if this was to be surgical. Access to a review process by the offender is also essential. The lawfulness of the USA model, whereby indeterminate sentencing is not passed until after the prison sentence has been served is unique to this jurisdiction. It is possible, that if such a system existed in Europe, it would be deemed to be in breach of the European Convention on Human Rights.

Further Research

Additional evaluation on recidivism of offenders in receipt of provisions for serious violent and sexual offenders would contribute to knowledge of the effectiveness of these provisions. Further evaluation of treatment approaches using comparable methodology would also be beneficial.

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