Understanding comorbidity between specific learning disabilities and developmental psychopathology

The overarching objective of CLDRC Project I is to use multiple converging methods to test why specific learning disabilities (SLDs) co-occur so often with other SLDs and with other disorders such as attention-deficit/hyperactivity disorder (ADHD), and anxiety. Three samples will be enrolled to accomplish the specific aims of Project I over the next five years. Project I and II will work together to collect a total sample of 600 consecutive referrals through our assessment clinics, including approximately 200 children from lower income families and significant subgroups with severe SLDs and multiple comorbidities. In addition to the clinic sample, Project I and Project II will also collaborate on a 5-year longitudinal follow-up study of 220 twins who participated in the CLDRC during the current funding period. Participants in both of these studies will come to Project I laboratories to complete a comprehensive battery that includes measures of basic and higher-order aspects of reading, math, and writing, nearly all neuropsychological constructs that are included in the most prominent cognitive models of SLDs and related psychopathology, and ratings of ADHD, SCT, anxiety, and other dimensions of psychopathology and functional impairment. To complement these two studies of children with SLDs, the third Project I sample will be a follow-up at age 30 of a sample that was first assessed in preschool, facilitating analyses of the development of SLDs over 25 years. Results will provide important new information regarding the structure of SLDs, the immediate and long-term implications of comorbidity between different SLDs and other related disorders, and the shared etiological influences and neuropsychological weaknesses that may lead to these comorbity.