Neuronal generators of posterior EEG alpha reflect individual differences in prioritizing personal spirituality

•High personal importance of religion/spirituality protects against MDD and is associated with greater posterior EEG alpha.•Those who expressed high importance only at 10-y followup did not show increased alpha.•Group differences in EEG alpha were clearest for individuals with a lifetime history of depression.•EEG alpha may index a common adaptive mechanism underlying affective regulation and personal spirituality. Prominent posterior EEG alpha is associated with depression and clinical response to antidepressants. Given that religious belief was protective against depression in a longitudinal study of familial risk, we hypothesized that individuals who differed by strength of spiritual beliefs might also differ in EEG alpha. Clinical evaluations and self-reports of the importance of religion or spirituality (R/S) were obtained from 52 participants, and again at 10-y followup when EEG was measured. EEG alpha was quantified using frequency PCA of current source densities (CSD-fPCA). Participants who rated R/S as highly important at initial assessment showed greater alpha compared to those who did not. Those who rated R/S important in both sessions showed greater alpha than those who changed their ratings. EEG differences were particularly well-defined for participants with lifetime depression. Findings extend the view of alpha as a marker for affective processes, suggesting an association with the ontogenesis of spirituality.