Psychopharmacology in children with intellectual disability

Children and adolescents with intellectual disability (commonly referred to as learning disability by the National Health Service (NHS) in the UK) have significantly higher rates of psychiatric morbidity than those without such disabilities (Emerson 2003). Recent major UK health planning documents have emphasised the role of local child and adolescent mental health services (CAMHS) in providing an inclusive service for this patient group, but currently there is neither consistent provision of such services nor any agreed consensus as to how they should be delivered. Consequently, children with intellectual disability who require psychiatric help may present to a variety of health agencies (CAMHS, specialist learning disability teams within generic CAMHS, community or hospital paediatric services, or lifespan psychiatry of learning disability services). It is probably still the case that much psychological morbidity is unrecognised because healthcare professionals hold false assumptions about the link between psychopathology and underlying cognitive deficit; the term ‘diagnostic overshadowing’ was coined to describe this phenomenon (Reiss 1982). Little is known about the past use of psychotropic medication to treat the mental health problems of children and adolescents with intellectual disability. However, it is likely that a restricted range, comprising principally tranquillising medication such as the older antipsychotic drugs (e.g. chlor­ promazine, haloperidol, thioridazine) and the anti­ histaminic sedative hypnotic agents trimeprazine tartrate and promethazine hydrochloride, was used to treat a broad range of challenging behaviours (Santosh 1999). More recently, the full range of psychopharmacological agents used within generic CAMHS and paediatric settings is also being used with this patient group. A survey of consultant psychiatrists who were either clinical specialists in child and/or adult intellectual disability or child and adolescent consultants with a special interest in the field confirmed this trend (Bramble 2007). The strongest research evidence in the field is to be found for the use of psychostimulants to treat attention­deficit hyperactivity disorder (ADHD) (Aman 2003) and for antipsychotics in the treatment of oppositional and aggressive behaviours commonly demonstrated by individuals with autism (McKracken 2002). A practical review of the research evidence emerging from this field has been provided recently in a clinical toolkit devised by the Royal College of Psychiatrists for clinicians working in paediatric learning disability services (Bernard 2009). The review undertaken here will examine the applications of the broad classes of psychotropic medication, suggest ‘best fit’ first­line agents for the more common symptom clusters encountered with young patients with intellectual disability and provide a number of illustrative case vignettes.