Manifestations of depression in people with intellectual disability

Abstract

The symptoms of 36 people with varying degrees of intellectual disability (ID) who had had an ICD-10 depressive syndrome in the preceding year were compared with 46 non-depressed people with comparable degrees of ID. Throughout the spectrum of ID, symptoms of depressed affect and sleep disturbance were significantly different between the groups. While symptoms in people with mild ID were reflected in the standard diagnostic criteria, this was not the case in people with moderate and severe ID. With increasing disability there was a move towards 'behavioural depressive equivalents' such as aggression, screaming and self-injurious behaviour. Diagnostic criteria for depression among people with severe ID, should place more emphasis on behavioural 'depressive equivalents'.

Problem behaviours and symptom dimensions of psychiatric disorders in adults with intellectual disabilities: An exploratory and confirmatory factor analysis

“…It has been suggested that problem behaviours are behavioural equivalents of depressive symptoms in adults with intellectual disabilities and should be included in diagnostic criteria (Smiley & Cooper, 2003). However, findings have been equivocal on whether problem behaviours should (Charlot et al,1993;Felce et al, 2009;Hurley, 2008;Kishore et al, 2005;Marston et al, 1997;Moss et al, 2000) or should not (Holden & Gitlesen, 2003;Sturmey et al, 2010;Tsiouris et al, 2003;Tsiouris et al, 2011) be considered as depressive equivalents. This creates uncertainty that is reflected in the classification systems, for example problem behaviours are included as symptoms of depression in the DC-LD (Royal College of Psychiatrists, 2001) but not in the DM-ID (Fletcher et al, 2007).…”

“…The majority of studies that have considered problem behaviours as equivalents of symptoms of psychiatric disorders have used a methodology that predefined groups of participants based on whether they met diagnostic criteria for depression that do not include problem behaviours (Charlot et al, 1993;Felce et al, 2009;Holden & Gitlesen, 2003;Hurley, 2008;Kishore et al, 2005;Marston et al, 1997;Moss et al, 2000;Tsiouris et al, 2011). This methodology has limited validity (Ross & Oliver, 2002) because the comparison groups are predefined using diagnostic criteria for depression that do not include problem behaviours.…”

“…Although this statistical modelling approach using factor analysis improves on the tautological problems in the studies using a two group, depression/non-depression method (Charlot et al, 1993;Felce et al, 2009;Holden & Gitlesen, 2003;Hurley, 2008;Kishore et al, 2005;Marston et al, 1997;Moss et al, 2000;Tsiouris et al, 2011) both studies used Pearson correlations for the initial matrix, and principal components analysis, which are unsuited to the analysis of categorical data (Norris & Lecavalier, 2010) and have shown to produce unstable solutions in Monte Carlo simulation studies (Snook & Gorusch, 1989). Other limitations of these studies were the small sample size (n=92) in one of the studies (Tsiouris et al, 2003) and neither study validated the EFA findings, for example using confirmatory factor analysis (CFA).…”

The assessment of mood in adults who have severe or profound mental retardation

“…those in ICD-10 (World Health Organisation, 1992) or DSM-IV (American Psychiatric Association, 1994) (see the retrospective analysis of earlier studies by Pawlarcyzk & Beckwith (1987) and Sovner & Desnoyers-Hurleys (1983); group comparison studies, e.g. Meins (1995) and Marston, Perry & Roy (1997) and a review article by Sturmey (1995)). Hence, these standard diagnostic criteria are regarded as appropriate for use with people with mild or moderate mental retardation.…”

“…These include informant reports of sleep (Charlot et al, 1993;Marston et al, 1997) and appetite changes (Charlot et al, 1993) and sad/depressed mood (Charlot et al, 1993;Marston et al, 1997).…”