The role of anxiety in the relationship between Phenylketonuria and working memory
Abstract
Phenylketonuria (PKU) is a rare genetic condition associated with disruption in the synthesis of tyrosine, a precursor for dopamine. Although early diagnosis and treatment largely prevent the severe impairments associated with untreated PKU, individuals with early-treated PKU (ETPKU) nonetheless experience significant neurocognitive sequelae, including difficulties in working memory (WM). ETPKU is also associated with an increased risk of psychiatric problems, most notably anxiety. Given the well-documented relationship between anxiety and impaired WM in the general population, it remains unclear to what extent WM difficulties and comorbid anxiety may be inter-related in the ETPKU population. To examine this issue, we recruited a sample of 40 adults with ETPKU and a demographically-matched sample of 40 healthy adults without PKU. WM performance and anxiety symptomatology were assessed using a variety of remote assessment methods (e.g., web-based neurocognitive tests, semi-structured interviews, report-based measures). As expected, the ETPKU group demonstrated poorer WM performance and higher anxiety as compared to the non-PKU group. In addition, anxiety moderated the relationship between metabolic control (as reflected by blood phe levels) and WM performance in the ETPKU group. The presence of elevated anxiety was associated with poor WM performance regardless of phe levels. For individuals with lower anxiety, there was a negative relationship between phe level and WM performance. This study highlights the importance of considering how metabolic control and comorbid conditions such as anxiety may contribute to neurocognitive difficulties experienced by individuals with ETPKU.
Degree
Ph. D.