The relation between borderline intellectual capacity and neurodevelopmental disorders

Introduction. Individuals with borderline intellectual capacity (BIC) have educational, social and occupational limitations that are similar to those of the mental retarded (MR), although to a lower degree. The condition that defines BIC is the detection of an intelligence quotient between 71 and 84. Unlike MR, patients with BIC have received little attention in medical journals and hence the cognitive characteristics of this group are still poorly defined. Aims. The purpose of this study was to assess the different neurodevelopmental disorders associated with BIC. Patients and methods. A group of 87 patients who had been diagnosed with BIC were selected, together with a control group. The clinical diagnoses were analysed and the results of the CBCL/6-18 survey from the two groups were compared. Results. The group of patients was found to have a high prevalence of neurocognitive disorders, such as attention deficit hyperactivity disorder (ADHD), learning difficulties and pervasive developmental disorders. The most frequent medical diagnosis was the effects of alcohol on the foetus. The results of the CBCL/6-18 in the group that was studied showed a behavioural profile that was very close to that described in patients with ADHD. Conclusions. Neurodevelopmental disorders, especially ADHD, exert a marked influence on intellectual capacity. Early detection and intervention could prevent many cases of BIC by lessening the sustained impact of a poor working memory linked to ADHD.