Recent developments in the study of behavioural phenotypes

This paper discusses issues arising from studies of the particular behavioural and psychopathological traits associated with genetic intellectual disability syndromes. These traits constitute what are now called behavioural phenotypes. The mechanism of inheritance of the Fragile X gene has now been demonstrated, and behavioural correlates identified. The behavioural disturbances associated with Williams syndrome are an example of new psychiatric disorders being identified through behaviour phenotype studies. A number of methodological principles should be followed before valid behaviour phenotypes can be formulated

Assessing emotional and behavioral problems in children with intellectual disability: Revisiting the factor structure of the Developmental Behaviour Checklist

The objective of the reported study was to reassess the factor structure of the Developmental Behaviour Checklist (DBC) in a large cross-cultural sample representing all levels of intellectual disability. Parent and teacher DBC ratings on a combined sample of 1536 Dutch and Australian children and adolescents (ages 3-22) with mild to profound intellectual disability were used. Principal components analyses produced five subscales: Disruptive/Antisocial, Self-Absorbed, Communication Disturbance, Anxiety, and Social Relating, explaining 43.7% of the total variance. Internal consistencies of these subscales ranged from .66 to .91. The revised factor structure of the DBC appears to be an improved and useful tool for assessing emotional and behavioral problems in children with intellectual disabilities

Prevalence of psychopathology in children and adolescents with and without intellectual disability

Background: The main objective of this study was to assess and compare the prevalence of a wide range of emotional and behavioral problems in children with and without intellectual disability (ID). Methods: We studied 1,041 non-residential children randomly selected from special schools for educable (IQ 60 to 80) and trainable (IQ 30 to 60) children without severe additional physical or sensory impairments, and compared them to 1,855 children randomly selected from the general population (both ages 6 to 18). Parents completed the Child Behavior Checklist (CBCL), and teachers the Teacher's Report Form (TRF). Results: Controlling for sex, age, and socioeconomic status, we found that both educable and trainable children had significantly higher mean scores on all CBCL and TRF scales than children without ID, except for trainable children on the scales Anxious/Depressed and Somatic Complaints. Almost 50% of children with ID had a Total Problem score in the deviant range compared to about 18% in children without ID. Compared to children without ID, the most prominent problem behaviors of educable children were Social Problems, Attention Problems, and Aggressive Behavior, and trainable children had an increased risk for Social Problems, Attention Problems, Withdrawn and Thought Problems. Conclusions: Elevated scale scores reflected differences between children with and without ID over a broad range of items, and not solely on items more likely to be related to developmental delay. Therefore, problem areas covered by the items in these scales deserve special attention in the mental health care of children with ID