title: Severe Intellectual Disability: Systematic Review of the Prevalence and Nature of Presentation of Unipolar Depression.
abstract: BACKGROUND
  The diagnosis of depression in severe and profound intellectual disability is challenging. Without adequate skills in verbal self-expression, standardized diagnostic criteria cannot be used with confidence. The purpose of this systematic review was to investigate the assessment and diagnosis of unipolar depression in severe and profound intellectual disability. The review aimed to examine the methods used to assess for depression. The secondary aim was to explore the frequency and symptoms of depression.
  
  
  METHODS
  The PRISMA (2009) Checklist for systematic review was followed, and a search of electronic databases was undertaken. Nine studies were included in the qualitative synthesis from over 2000 records identified.
  
  
  RESULTS
  The quality of the studies was assessed and scored, with a wide range of results. Individual studies scored between 2 and 7 of a maximum possible score of 8. The diagnostic tools utilized by each of the studies were assessed and compared.
  
  
  CONCLUSIONS
  In terms of the methods used to assess for depression, results were varied. This was due to the heterogeneous nature of the individual study designs. The Aberrant Behaviour Checklist consistently showed promise, in particular when combined with other instruments or clinical examination. Qualitative analysis of the selected studies has shown a wide variation in the quality of primary research in this field, with more required to make firm conclusions regarding the diagnosis, frequency and presentation of depression in severe and profound intellectual disability.
authors.affiliation: Core Psychiatry Trainee, Cwm Taf University Health Board, Royal Glamorgan Hospital, Pontyclun, Wales, UK.
authors.forename: Catherine
authors.initials: C
authors.lastname: Walton
authors.affiliation: Clinical Professor, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK.
authors.forename: Mike
authors.initials: M
authors.lastname: Kerr
mesh_terms: D015897:Comorbidity; D003865:Major Depressive Disorder / Q000453:epidemiology / Q000503:physiopathology*; D006801:Humans; D008607:Intellectual Disability / Q000453:epidemiology / Q000503:physiopathology*
keywords: depression; intellectual disability; learning disability; mood disorder; psychiatry; severe intellectual disability