Table.1.

Overview of studies assessing autosuggestion and related phenomena

Phenomena measured	Definitions	Sample size	Dependent variables	Control group	Methods	Results	References
Autosuggestion	Not given	N total = 60, aged ≥ 60, 30 per gr	Quality of life ratings Levels of serum cortisol concentration Levels of immunity markers	Yes	A tapes QoL chart Measurements in cortisol level and psycho-neuroendocrine immunology markers by magnetic resonance spectroscopy	Higher QoL scores in A group Serum cortisol reaching healthy norms in A gr. Increase in immunity markers in A group	Sari et al. (2017)
Posthypnotic suggestion, autosuggestion	‘Autosuggestion refers to the process of implementing a mental change in oneself (e.g. by repeating suggestions to oneself and by engaging in goal-directed imagery).’	N total = 32, 16 per gr	Number of bids for sweet/salty snacks	No	fMRI Questionnaire Behavioural: decision making	Snack devaluation by both H and A Effects stronger in hypnosis Decreased BOLD signal in the vmPFC	Ludwig et al. (2014)
First three autosuggestive phases of AT, motor imagery	Not given	N total = 38, 19 per gr	BOLD signal levels in experimental tasks and resting state	Yes	fMRI Questionnaires Motor imagery	Left parietal cortex activation during the first two steps of AT in contrast to resting state in controls Higher activation of prefrontal and insular cortices in AT group Higher activation in sensory-motor areas (*) during imagery task in AT group as compared to controls	Schlamann et al. (2010)
Verbal suggestion/placebo	‘Placebos—a set of ‘words, rituals, symbols and meanings’ that can change the brains of the patients’ (Benedetti et al. 2011)	N = 24, 14 in placebo-like gr, 10 in control gr	Amplitude measurements of late SEPs (N140 and P 200) before and after treatment	Yes	Electrical stimulation Baseline session, experimental manipulation and final recording	No increase of tactile sensation after the treatment No modification in late SEPs	Fiorio et al. (2014)
Positive and negative Suggestion/Placebo effects	Not given	N = 36, 13 per gr	Pain threshold, pain tolerance and pain endurance measures	Yes	Hand immersion in ice cold water	Higher pain thresholds, greater pain tolerance and greater pain endurance in PP gr compared to other groups	Staats et al. (1998)
Placebo analgesia effects	Not given	N = 24 (exp 1) N = 23 (exp 2)	BOLD signal on placebo analgesia PFC activation during pain anticipation Subjective pain ratings	Yes	fMRI Painful stimulation Placebo analgesia	Reduced activity in the thalamus, insula, and ACC after placebo analgesia Increased activity during anticipation of pain in PFC and midbrain Greater reported pain for control than placebo condition	Wager et al. (2004)
Autogenic training (AT), cognitive selfhypnosis (CSH)	Not given	N = 156, 58 outpatient neurological patients, 48 community members, 40 students	Treatment outcomes for chronic headaches Relations of level of hypnotizability to treatment outcome Subject recruitment on treatment outcome Use of analgesic medication	Yes	Pretreatment, post-treatment (week 8) and follow-up (week 35)	Reduction in HI scores in experimental groups compared to controls during treatment Reduction in HI scores in AT gr at post treatment differed sig. from WLC gr No sig. differences between treatment conditions at follow-up No sig. reduction in analgesics use between all groups	Ter Kulie et al. (1994)
Imagery	Not given	N = 40	Pressure pain thresholds	Yes	Pressure pain (induced by other, self, or other while imagining the pressure to be self-induced)	Elevated pain thresholds in self and imagery conditions (sig. differences between all conditions)	Lalouni et al. (2021)
Hypnosis	‘Ideomotor movement’—hypnotic phenomenon in which self-produced actions are attributed to an external source	N = 6 highly hypnotisable	Neural correlates of active movements correctly attributed to the self or misattributed to an external source	Yes	PET Hypnotic induction Deepening induction	Sig. higher activations in the PC in active movements attributed to an external source compared to identical movements attributed to the self	Blakemore et al. (2003)
Spiritual meditation, secular meditation, muscle relaxation	Not given	N = 83	Pain tolerance Headache frequency Mental and spiritual health variables	Yes	Cold pressor task	Greater decreases in the headache frequency in spiritual meditation gr compared to other groups Greater increases in pain tolerance, headacherelated self-efficacy, daily spiritual experiences and existential well-being in spiritual meditation gr compared to other groups	Wachholtz and Pargament (2005)

A autosuggestion, ACC anterior cingulate cortex, AT autogenic training, BOLD blood oxygen level-dependent, exp experiment, gr group, H hypnosis, HI headache index, NP negative placebo, PP positive placebo, PC parietal cortex, PET Positron Emission Tomography, PFC prefrontal cortex, vmPFC ventromedial prefrontal cortex, SEPs somatosensory evoked potentials, QoL quality of life, WLC waiting list control

*AT: postcentral BA 7 and BA 5, sup. frontal BA 6, inf. parietal (BA 40); controls: postcentral BA 5, sup. frontal BA 6, inf. parietal (BA 40)