Objective: Although early diagnosis and treatment prevent the severe impairments associated with untreated phenylketonuria (PKU), individuals with early treated PKU (ETPKU) nonetheless experience significant neurocognitive and psychological sequelae, including difficulties in working memory (WM) and increased risk of anxiety. The primary objective of the present study was to examine the extent to which anxiety may moderate the relationship between ETPKU and WM performance.
Method: A sample of 40 adults with ETPKU and a demographically comparable sample of 40 healthy adults without PKU completed a comprehensive assessment of WM performance and anxiety symptomatology. Data were collected using a variety of remote assessment methods (e.g., web-based neurocognitive tests, semistructured interview, report-based measures).
Results: The ETPKU group demonstrated significantly poorer WM performance as compared to the non-PKU group. The groups did not differ significantly in anxiety; however, high anxiety was more common in the ETPKU group (53% of sample) than the non-PKU group (33%). A significant interaction between anxiety, metabolic control (as reflected by Phe levels), and WM performance was observed for the ETPKU group. Individuals with high anxiety and/or high Phe levels (> 360 μmol/L) performed poorer than the non-PKU group. Individuals with low anxiety and relatively low Phe levels (< 360 μmol/L) performed comparably to the non-PKU group.
Conclusions: Anxiety was found to moderate the relationship between Phe levels and WM performance in individuals with ETPKU. This finding underscores the importance of accounting for anxiety when evaluating neurocognitive performance in individuals with ETPKU whether for research or clinical purposes. (PsycInfo Database Record (c) 2024 APA, all rights reserved).