PSYCHIATRIC-DISORDERS IN ADULT PATIENTS WITH EARLY-TREATED PHENYLKETONURIA

Objective. To determine psychiatric disorders in patients with phenylk etonuria (PKU) and to test whether biochemical control, intellectual f unctioning, white matter abnormalities visible on magnetic resonance i maging (MRI), and/or style of parenting influence psychopathology. Des ign and Subjects. This cross-sectional study consisted of 35 PKU patie nts 17 to 33 years of age (mean: 22.2). From a total of 67 patients, 3 patients were selected because of other causes of possible brain dama ge. Then 35 patients were randomly drawn with comparison with a contro l sample (n = 181) from an epidemiologic study. Methods. We used a sta ndardized, highly structured, face-to-face interview; intelligence quo tient (IQ) test; cranial MRI (n = 26); and monitoring of plasma phenyl alanine. Results. The overall rate of psychiatric disorders was 25.7% in PKU patients and 16.1% in controls. This difference was not statist ically significant. The pattern of psychiatric disturbances was differ ent for PKU patients and controls (Fisher's exact test): in PKU patien ts, externalizing disorders were reduced (PKU: not present, controls: 7.8%), whereas internalizing disorders (PKU: 25.7%, controls: 8.3%) we re increased. International Classification of Diseases, version 10, di agnoses were predominantly those of the depressive category and more f requent in women (8 of 18 females and 1 of 17 males). A correlation be tween IQ and both biochemical control up to 12 years of age and school education of parents was confirmed. No correlation was found between the severity or pattern of psychiatric disturbances and school educati on of parents, biochemical control, IQ, or the extension of MRI-visibl e, white matter abnormalities. It was found that a restrictive control ling style of parenting is a risk factor for the development of psychi atric symptoms. Conclusions. Our results support a psychological persp ective for the development of psychiatric symptoms in PKU. Thus, optim izing medical treatment necessary to prevent brain damage should be ac companied by psychiatric monitoring and psychological support for the families.