PKU in adolescents: rationale and psychosocial factors in diet continuation.

Follow-up of early-treated children with PKU has shown that diet discontinuation in childhood presents risks of cognitive and emotional dysfunction in a substantial number of adolescents and young adults. This dysfunction includes IQ loss, mental processing abnormalities, learning difficulties, anxiety and personality disorders. In addition, neurologic deterioration has been reported in several such individuals. As a consequence of this current understanding of PKU, diet continuation, at least through adolescence and in the young adult years, is now recommended. Many centers are extending this to a policy of "diet for life". This represents a major challenge to adolescents and their families. Metabolic control using the criteria applied during childhood is virtually impossible to achieve past 12 years of age. Time constraints, social pressures, financial limitations and growing independence from the family combine to interfere with dietary control. Added to these difficulties are the biological changes during teenage years which reduce phenylalanine tolerance. To meet these challenges, we have identified a number of psychosocial factors that interfere with adherence to medical recommendations. The factors most highly related to metabolic control were social support for the diet and positive perceptions of treatment. This information has led to the development of support programs for adolescents and young adults with PKU.(ABSTRACT TRUNCATED AT 250 WORDS)