The findings suggest a relationship between psychiatric problems and reading problems in adolescence independent of ADHD and imply that reading assessments for adolescents who are having problems in school may not only improve their reading skills but also identify those in need of psychiatric care, the investigators said.
Gene CYP2D6 and Risperidone
The activity of the CYP2D6 gene may affect how children with developmental disorders respond to risperidone and release prolactin, based on data from a small study by Dr. Pieter W. Troost of the University of Groningen (the Netherlands) and colleagues.
Previous studies have shown that low to medium doses of risperidone in children may increase prolactin to dangerous levels that can be associated with side effects such as sexual dysfunction and impaired growth.
To assess the role of the CYP2D6 gene on risperidone metabolization and prolactin levels, the investigators reviewed data from 25 children aged 5–15 years with pervasive developmental disorders (J. Clin. Psychopharmacol. 2007;27:52–7).
Gene analysis showed that 5 children (20%) had no functional CYP2D6 genes, 6 (24%) had one functional gene, 12 (48%) had two functional genes, and 2 (8%) had three or more functional genes. The children were treated with an average daily risperidone dose of 0.06 mg/kg.
After 8 weeks of treatment, elevated serum prolactin levels appeared to be positively, but not significantly, correlated with a greater number of CYP2D6 genes. Elevated serum prolactin was, however, positively and significantly correlated with an increased dose of risperidone and an increased concentration of serum 9-hydroxyrisperidone. Children with more functional CYP2D6 genes had higher levels of the metabolite 9-hydroxyrisperidone.