Bilateral Electrodermal Activity and Psychoticism: Epq-r P Score Correlates with Scl and Eeg Asymmetry

Several clinical studies have reported that schizophrenics show higher electrodermal activity (SCL and SCR) on their right compared to their left hand (R>L). According to Eysenck's personality model, schizophrenia is located at the extreme pole of the psychoticism dimension (P). Thus, it could be hypothesized that normal Ss with high P scores will also show a R>L pattern, especially in comparison to Ss with low P scores. Reported are the results of two studies in which healthy female Ss were given the Eysenck Personality Questionnaire (EPQ-R) before viewing emotionally charging and neutral stimuli in a visual half-field paradigm. Phasic and tonic electrodermal parameters were recorded from the pal-mar surface (study I) and medial phalanges (study II) of both hands. In addition, study II recorded continuously CNS activity (11 EEG leads). In study I, Ss with high P scores showed increased electrodermal activity on the right compared to the left hand (R>L). Ss with low P scores tended to show increased activity on their left hand (L>R). In study II, SCL hand differences (R-L) were significantly correlated with P scores and with EEG alpha asymmetry, i.e. relative larger right hand levels were associated with higher P scores and with relative more left frontal and temporal activation. Higher P scores were also significantly associated with relative left hemispheric activation in frontal, temporal and parietal regions. The present results suggest a relationship between EDA asymmetry, asymmetric hemispheric activation and psychoticism score. High P scorers show similar asymmetrical EDA (R>L) and EEG (LH>RH) patterns observed in some types of schizophrenia. Concerning hypotheses about an asymmetrical hemispheric influence on bilateral electrodermal activity the results strongly support models of contralateral excitatory or ipsilateral inhibitory cortical control.