Supplementary Material for: Plasma allopregnanolone and sex hormone responses to stress induction: contributors to the formation of intrusive memories

Introduction: Intrusive memories are a central identifying symptom of post-traumatic stress disorder (PTSD), and their development can be modelled in experimental settings with the trauma film paradigm. Neurosteroids and sex hormones such as allopregnanolone and testosterone, respectively, have recently become potential targets for PTSD pharmacological treatment due to their influence on the stress response.
Methods: In the current study 49 healthy female participants underwent stress induction and viewed a trauma film. Plasma allopregnanolone, testosterone, and cortisol responses to stress induction and the trauma film were recorded and stress-induced responses were modelled as predictors of intrusive memory frequency using negative binomial regression models.
Results: Compared to baseline, plasma allopregnanolone and cortisol levels, along with subjective stress, were significantly higher after the stress induction. Plasma cortisol and subjective stress responses to the stress induction task significantly predicted intrusive memories. Allopregnanolone and testosterone did not predict intrusive memories, though allopregnanolone and cortisol stress responses were significantly correlated.
Discussion: These findings expand our current understanding of the biochemical processes of intrusive memory formation under stress. Additionally, changes in allopregnanolone were observed in response to stress, which contributes towards the discussion of neurosteroids and sex hormones as potential pharmacological targets for the treatment of PTSD.