Relation between intelligence and psychopathology among preschoolers.

Examined the relation between intelligence and psychopathology in a nonclinical sample of 510 children ages 2 to 5 years. Psychopathology was measured using both quantitative, dimensional methods (Child Behavior Checklist [CBCL]) and taxonomic methods (the Diagnostic and Statistical Manual of Mental Disorders [3rd. ed., Rev.; DSM-III-R; American Psychological Association, 1987]). IQ scores were derived from either the McCarthy Scales of Children's Abilities or the Bayley Scales of Mental Development. Based on quantitative, dimensional data, results support similar findings among older children and clinical populations that lower McCarthy general, verbal, and perceptual-performance IQ scores are associated with various types of psychopathology. Results were also consistent for the DSM-III-R data. Bayley IQ scores did not predict CBCL psychopathology or DSM-III-R Disruptive Disorders, but they did predict the presence of a DSM-III-R diagnosis. Early identification of intellectual deficits among preschoolers ages 3 to 5 may help to prevent later school difficulties and severe psychopathology.