Objectives: To develop a structural equation model of negative affectivity (NA) that involves interaction of glucocorticoid receptor (GR) signaling, personality dimensions and recent stressful life events.
Methods: Seventy participants - 35 diagnosed with major depression and 35 healthy controls, were enrolled in the study. Morning plasma cortisol levels were determined by chemiluminescent immunometric assays. Molecular parameters (total nuclear and cytoplasmatic GR, nuclear GR phosphorylated at serine 211 (pGR-211) and at serine 226 (pGR-226) and cytoplasmic FKBP51) were analysed from peripheral blood lymphocytes by Western blot. NA, personality dimensions and stressful life events were assessed by self-report instruments.
Results: GR signalling parameters had direct independent effect on measures of NA, with pGR-226 levels showing the strongest correlation, followed by FKBP51 and pGR-211 levels. Neuroticism and extraversion also demonstrated strong independent effect on NA, while recent stressful events did not predict NA directly, but demonstrated a significant effect on personality dimensions. Cortisol, total nuclear GR and total cytoplasmatic GR levels were excluded from the model due to non-significant correlations with NA.
Conclusions: Negative affectivity is a transdiagnostic factor in vulnerability to affective disorders and possible therapeutic target. Molecular signature of negative affectivity should incorporate GR phosphorylation with other known biological underpinnings.
Keywords: HPA; depression; modelling; neuroticism; stress.