Induced feelings of external influence during instructed imaginations in healthy subjects

Kathrin N Eckstein; David Rosenbaum; Nadine Zehender; Sonja Pleiss; Sharon Platzbecker; Anne Martinelli; Matthias L Herrmann; Dirk Wildgruber

doi:10.3389/fpsyg.2022.1005479

Induced feelings of external influence during instructed imaginations in healthy subjects

Front Psychol. 2022 Nov 1:13:1005479. doi: 10.3389/fpsyg.2022.1005479. eCollection 2022.

Authors

Kathrin N Eckstein¹, David Rosenbaum¹, Nadine Zehender^{1

2}, Sonja Pleiss¹, Sharon Platzbecker¹, Anne Martinelli^{1

3}, Matthias L Herrmann^{1

4}, Dirk Wildgruber¹

Affiliations

¹ Department of Psychiatry and Psychotherapy, Tübingen Center for Mental Health (TüCMH), University of Tübingen, Tübingen, Germany.
² Department of Psychiatry and Psychotherapy, University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
³ School of Psychology, Fresenius University of Applied Sciences, Frankfurt am Main, Germany.
⁴ Department of Neurology and Neuroscience, Medical Center, University of Freiburg, Freiburg, Germany.

Abstract

The psychopathological phenomenon of delusions of influence comprises variable disturbances of the self-environment-border leading to the feeling of external influence on thoughts, feelings, impulses or behaviors. Delusions of influence are a hallmark in psychotic illness, but nevertheless, attenuated forms can also appear in healthy individuals. Here we present a newly developed paradigm to induce and assess feelings of external influence during instructed imaginations in healthy individuals. In the current study, we asked 60 healthy individuals to visually imagine different objects. To induce feelings of external influence, we applied one of three different physical setups (low-amplitude transcranial direct current stimulation, eye contact, or skin-to-skin hand touch), and informed the participants whether or not an external influence was attempted during the respective trial. The physical setup (setup vs. no setup, Z = -3.847, p < 0.001, r = 0.497) as well as the information given to the participants (confirmation vs. negation, Z = -5.218, p < 0.001, r = 0.674) alone were able to modulate the feeling of external influence in all three interventions. The impact of information (whether influence was attempted or not attempted) significantly exceeded the impact of the physical setup on the ratings of experienced external influence (Z = -2.394, p = 0.016, r = 0.310). Moreover, the response latency correlated with the estimated feeling of external influence (r _S = 0.392, p = 0.002). Additional analyses addressed the influence of the emotional content of imagined objects and examined the intensity and emotional valence of the imaginations. Further supplemental analyses correlated external influence estimation of the participants with other psychopathological measures (trait markers for supernatural beliefs, proneness to hallucinations, and delusions and attributional style). In conclusion, this study endorses a quantitative model of psychopathological characteristics, in this case feelings of external influence that can be induced by external cues.

Keywords: delusion of influence; emotional valence; eye contact; hand touch; psychotic symptoms; response latency; sense of agency; tDCS.