Abstract
Background: Anxiety disorders are amongst the most prevalent mental health conditions worldwide and are theorised to be associated with altered interoception (the perception and control of internal bodily states). Such alterations may contribute to maladaptive interpretations of bodily sensations and the maintenance of anxiety symptoms. Although selective serotonin reuptake inhibitors (SSRIs) are effective treatments for anxiety disorders, how SSRI treatment influences interoceptive learning (i.e. how beliefs regarding bodily state are updated) remains unclear. The present study aimed to address this gap in the literature by examining the effects of SSRIs on respiratory interoceptive learning in a clinically anxious population.
Methods: Two cohorts of individuals with anxiety disorders were assessed: individuals beginning a new course of SSRI treatment (n = 40) and those already stable on an SSRI regimen (n = 25). Participants undertook a breathing learning task (BLT; Brand et al., 2024; Harrison et al., 2021b), a dynamic learning paradigm using interoceptive inspiratory resistances, across two sessions at least six weeks apart. Behavioural responses from the BLT were modelled using a Rescorla-Wagner learning model to estimate learning rate and inverse decision temperature parameters, and measures of response certainty were calculated from the raw data. Measures of maladaptive (GAD-7) and trait anxiety (STAI-T) were also collected.
Results: Initiation of SSRI treatment was associated with significant reductions in maladaptive and trait anxiety, consistent with previous findings. However, learning rate, inverse decision temperature, and response certainty remained broadly stable across groups and time. Within the treatment group, reductions in learning rate demonstrated a preliminary trend-level association with reductions in trait anxiety. Increases in response certainty were moderately associated with reductions in maladaptive anxiety, with a similar association observed with trait anxiety.
Implications: Overall, the findings provide limited evidence that SSRI treatment substantially alters respiratory interoceptive learning processes for individuals with anxiety disorders and may instead reflect relatively stable processes that are only modestly associated with changes in anxiety symptoms. Further investigation using a wider sample of anxiety levels and more comprehensive computational methods may help clarify the relationship between anxiety, interoceptive learning, and SSRI treatment.