Assessment & Research

Schizophrenia-spectrum psychoses in people with and without intellectual disability.

Bouras et al. (2004) · Journal of intellectual disability research : JIDR 2004
★ The Verdict

Adults with both intellectual disability and schizophrenia-spectrum psychosis show worse symptoms and skills than those with psychosis alone, so they need stronger community supports.

✓ Read this if BCBAs working with adults who have dual diagnoses in day or residential programs.
✗ Skip if Clinicians serving only children or clients without psychosis.

01Research in Context

01

What this study did

Researchers compared adults who have both intellectual disability and schizophrenia-spectrum psychosis with adults who have only schizophrenia-spectrum psychosis.

They looked at symptom levels and everyday living skills in both groups.

02

What they found

The group with both conditions showed more severe negative symptoms, like flat mood and little speech.

They also had poorer daily living skills than the group with schizophrenia alone.

03

How this fits with other research

Lai et al. (2011) later tracked the same dual-diagnosis group in Taiwan and found they stay twice as long in hospital and cost twice as much per stay, turning the clinical picture into hard service-use numbers.

Van der Molen et al. (2010) showed these clients also struggle to explain simple steps in a dice game, adding communication deficits to the symptom list.

Martorell et al. (2011) surveyed families and found caregivers of the dual-diagnosis group report the highest burden of any group, linking patient symptoms to home stress.

04

Why it matters

When you see an adult with ID and suspected psychosis, expect more severe negative symptoms and poorer functioning than psychosis alone. Plan longer skill-teaching sessions, involve speech targets, and loop in family support early. The data say these clients use hospitals more and exhaust caregivers faster, so push for proactive community supports before crisis hits.

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02At a glance

Intervention
not applicable
Design
quasi experimental
Sample size
106
Population
intellectual disability
Finding
negative

03Original abstract

BACKGROUND: Although there is an increased risk of schizophrenia-spectrum psychoses (SSP) in people with intellectual disability (ID), there is a paucity of research evidence into clinical presentation of the disorder in comparison with research into SSP in people without ID. AIMS: The aims of the study were to compare clinical, functional, and social factors in patients with mild ID (ICD-10: F70) and SSP (ICD-10: F20-9) attending a specialist mental health service for people with ID, with a control group of patients without ID but with SSP attending a generic adult mental health (GAMH) outpatient clinic. METHOD: A total of 106 patients with SSP (53 with ID and 53 from GAMH) were assessed on psychopathological symptoms, functioning scales and quality of life. They were compared using chi-squared and regression analysis where appropriate. RESULTS: People with ID and SSP appear to be more debilitated by the co-occurring disorder than those with the same disorder but without ID. Increases in observable psychopathology and "negative" schizophrenic symptoms, and decreased functional abilities were observed in the group with ID when compared to the GAMH group. The clinical implications of these findings are discussed.

Journal of intellectual disability research : JIDR, 2004 · doi:10.1111/j.1365-2788.2004.00623.x