Frontal asymmetry and physiological responses in religious and spiritual problems with and without conversion

Religious conversion is often associated with a negative emotional state accompanied by profound changes in sacred beliefs, values, attitudes, and practices. This negative emotional state is referred to as "Religious or Spiritual Problem" (RSP) in the revised 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR, 2022). The physiological and neuronal correlates of RSP and religious conversion are not known. Therefore, we measured lateralized frontal alpha-asymmetry, saliva cortisol levels, and heart rate in 24 individuals who experienced religious conversion with RSP, 23 individuals with RSP without religious conversion, and 20 problem-free controls with matched religiosity. In the baseline condition, participants read newspapers and listened to non-religious music; in the religious condition, they read Bible verses and listened to sacred music. Relative to the controls, both groups with RSP showed stress responses in the religious condition, including increased frontal alpha-asymmetry (left > right frontal activation), elevated saliva cortisol concentrations, and higher heart rate. Participants experiencing religious conversion displayed higher frontal alpha-asymmetry than those without conversion, but the cortisol levels and heart rate responses were similar in converters and non-converters. These results indicate that religious conversion with RSP demands a higher cognitive load than RSP alone.