Table 2.

Included studies

Study	Design	N (Females)	Sample	Induction method	Target disorder/symptom	Outcome
Aslaksen and Lyby3	Mixed design	111 (76)	Healthy volunteers	Verbal information	Pain	Significantly larger nocebo hyperalgesic effect on pain report in females than in males
Aslaksen et al4	Within subjects design	33 (17)	Healthy volunteers	Verbal information	Pain	Significant placebo effect on pain unpleasantness and the P2 component in the EEG in males, but not in females
Bjørkedal and Flaten44	Mixed design	23 (7)	Healthy volunteers	Verbal information	Pain	Significant placebo effect on the P2 component in males, but not in females
Aslaksen and Flaten43	Within subjects design	63 (32)	Healthy volunteers	Verbal information	Pain	Significant placebo effect on pain intensity in males, but not in females
Flaten et al48	Mixed design	84 (47)	Healthy volunteers	Verbal information	Pain	Significant placebo effect on pain tolerance in males, but not in females
Butcher and Carmody5	Within subjects design	20 (10)	Healthy volunteers	Verbal information	Pain	Significant placebo effect on pain tolerance in males, but not in females
Krummenacher et al52	Between-groups design	49 (23)	Healthy volunteers (Children)	Verbal information	Pain	Placebo effect on heat pain threshold in boys and girls, but larger effect in girls compared to boys
Theysohn et al56	Within-subjects design	30 (15)	Healthy volunteers	Verbal information	Pain	Placebo effect on pain report in both males and females Significantly larger placebo effect on neural modulation in males compared to females
Colloca et al29	Between-groups design	109 (54)	Healthy volunteers	Verbal information	Pain	Placebo response enhanced and cortisol levels decreased significantly by vasopressin in females, but not in males
Swider and Babel6	Between-groups design	84 (42)	Healthy volunteers	Conditioning	Pain	Nocebo effect in males and females, but significantly larger nocebo effect on pain report in females than in males
Oken et al22	Between-groups design	40 (20)	Healthy volunteers	Verbal information	Cognitive performance	Significant placebo effect on choice reaction time in males, but not in females
Haltia et al23	Within-subjects design	24 (12)	Healthy volunteers	Verbal information	Dopaminergic functioning	Significant placebo effect on reported drug effect in females, but not in males
Kelley et al50	Between-groups design	289 (216)	Patients with IBS	Verbal information	IBS symptoms	Significantly larger placebo effect on IBS symptoms in females than in males
Klosterhalfen et al24, experiment 1	Within-subjects design	48 (24)	Healthy volunteers	Conditioning	Nausea	Significant nocebo effect on rotation tolerance in females, but not in males
Klosterhalfen et al24, experiment 2	Within-subjects design	48 (24)	Healthy volunteers	Verbal information	Nausea	Significant nocebo effect on rotation tolerance in males, but not in females
Faasse et al47	Between-groups design	82 (51)	Healthy volunteers	Conditioning	Symptoms associated with intake of an inert medication (participants was informed that the medication was a beta-blocker, but in fact they received a placebo).	Significant nocebo effect on total reported symptoms and symptoms attributed to medication in females, but not in males
Lorber et al53	Mixed design	86 (51)	Healthy volunteers	Conditioning	Symptoms associated with inhalation of an inert environmental toxin (participants was informed that the medication was a suspected environmental toxin, but, in fact, it was a placebo)	Significant nocebo effect on symptom report in females, but not in males
Abrams and Kushner25	Between-groups design	41 (25)	Participants were diagnosed with social phobia	Verbal information	Mental distress, fear of negative evaluation	Significant placebo effect on mental distress in males only

Abbreviations: EEG, electroencephalogram; IBS, irritable bowel syndrome