Alzheimer's disease (AD) is a progressive neurological disease. In early stages, AD is characterized by the aggregation of amyloid beta (Aβ) and hyperphosphorylated tau proteins in the brain,1 and worsening memory.2, 3 In the absence of disease‐modifying treatments, there is an urgent need to identify modifiable risk factors that are associated with these biomarkers, which can be targeted to prevent future AD.

In recent decades, a number of psychological risk factors for cognitive decline and AD have been identified.4 These include depression5-7 and anxiety.8-10 While these risks have generally been considered independently, the Cognitive Debt hypothesis suggests that a mechanism frequently present in these psychological risk factors—repetitive negative thinking (RNT)11—may underlie the risk associated with each factor.4

Repetitive negative thinking (also termed perseverative cognition) is a behaviorally measurable cognitive process that encompasses future‐ (worry) and past‐ (rumination) directed thoughts,12 and describes the thought process rather than its time orientation or content. It is relatively stable13 but like other traits, can also be modified through intervention.14, 15 While RNT is a comparatively new term, its components, rumination and worry, have been associated with memory and executive function in diverse populations.16-22 The behavioral evidence, we suggest, implicates RNT as a potential common pathway that contributes to increasing AD risk. RNT's relationship with neurobiological AD markers, amyloid and tau, has not yet been empirically examined; however, memory‐related worries have been associated with higher amyloid burden in individuals with subjective cognitive decline.23, 24 The current study sought to examine the relationship between (1) RNT and longitudinal cognitive change, and (2) RNT and AD pathologies using neuroimaging markers of Aβ and tau, compared to the relationships between symptoms of depression and anxiety and these markers.