Mental disorder is defined broadly across classification systems and legislation worldwide (see ICD-10, DSM-5 and World Health Organization definitions, all of which include intellectual disability within the definition). It is difficult to understand why Hollins et al seek to remove only intellectual disability and autism from the definition of mental disorder whereas all other mental illnesses and disorders would fall within the category.^{Reference Hollins, Lodge and Lomax1} It has never been the case that mental disorder only refers to episodic or psychotic illnesses. Dementia, acquired brain injury and personality disorder equally fall within the conditions where mental health legislation can apply. The concern seems to be ‘stigma’. Removing intellectual disability and autism from the definition of mental disorder will not result in less stigma. These conditions have carried significant stigma well before such legislation was in place, and unfortunately will continue to do so for some time to come.

There seems little justification for separate legislation only in relation to these two neurodevelopmental disorders. It would appear to be far better to protect rights by being included in broader mental health and incapacity legislation. The experience of New Zealand (the only jurisdiction that has removed intellectual disability from its mental health legislation) was that this resulted in separate legislation that replicated the rights and protections in mental health legislation (unnecessary duplication) while eroding the clinical expertise available to individuals and services.^{Reference McCarthy and Duff2} There is no evidence of significant positive outcomes for people with intellectual disability or autism being removed from definitions of mental disorder. The New Zealand experience resulted in more people with intellectual disability going to prison and a loss of clinical expertise.

It seems extraordinary that someone of the experience and expertise of Baroness Hollins could truly be of the view that all individuals could be managed within their home environments, no matter the level of challenging behaviour or the risk posed to others. The failure of the Transforming Care programme to substantially reduce the number of individuals receiving in-patient care (while transferring more individuals from National Health Service care to independent providers) highlights that this is an overly simplistic view that does not address the complexity of the underlying issues. Appropriate environments and highly trained staff can have significant positive outcomes for individuals, improving their quality of life. However, for some, significant levels of physical and/or sexual violence towards others requires provision beyond what can effectively be provided in isolated community services. In Scotland, the ‘Coming Home’ report noted that physical and sexual violence were the main causes of community placement breakdown, with individuals with both intellectual disability and autism being particularly difficult to manage outwith specialist health settings.^{Reference MacDonald3}

Hospital-based services can undoubtedly benefit from increased resources and investment in order to fulfil their role as intended. The main issues facing specialist in-patient settings are delayed discharges and the lack of appropriate community provision for individuals who no longer require in-patient care. Removing intellectual disability and autism from the definition of mental disorder will do nothing to address this lack of provision and runs the considerable risk of poorer physical and mental health outcomes for this vulnerable group.