F17
Conditions
Interventions
Group 1: Hypnosis for smoking cessation: A standardised hypnosis session of approximately 45 minutes. The session begins with a relaxation induction in which participants focus their gaze on a fixed p
Sponsors
Carl von Ossietzky Universität Oldenburg Fakultät VI – Medizin und Gesundheitswissenschaften Department für Psychologie, Neuropsychology Lab
Eligibility
Sex/Gender
All
Age
18 Years to 55 Years
Inclusion criteria
Inclusion criteria: Regular smokers (=10 cigarettes/day for at least 2 years); aged 18–55; sufficient English proficiency (B1 or higher); no current pregnancy; no implanted metallic devices in the head; no pacemaker; no epilepsy; no psychiatric or neurological disorder affecting the central nervous system. Sample size determination: An a priori power analysis (G*Power) for the Condition × Time interaction in a 2×2 mixed ANOVA indicated that 34 participants (17 per group) are required to detect a moderate effect (Cohen’s f = 0.25; partial ?² = 0.06; a = 0.05; power = 0.80; assumed pre–post correlation r = 0.50). The planned sample of 40 (20 per group) therefore provides power exceeding 0.80 for a moderate interaction effect; smaller effects may go undetected. Because generalised mixed models have no closed-form power analysis, power for daily cigarette consumption was determined by Monte Carlo simulation (1000 datasets per scenario, negative-binomial model with a random person intercept). With N = 40 (20 per group), three measurement days pre and post, and an assumed reduction of 5% (control) vs. 30% (active), power for the Condition × Time interaction is approximately 0.80; smaller intervention effects are underpowered with this sample.
Exclusion criteria
Exclusion criteria: Pregnancy; implanted metallic devices in the head; cardiac pacemaker; epilepsy; psychiatric or neurological disorder affecting the central nervous system; insufficient English proficiency (below B1); fewer than 10 cigarettes per day or smoking history of less than 2 years.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| 1. Neural cue reactivity to smoking-related stimuli, operationalised as the difference in LPP amplitude (mean amplitude in the 400–800 ms window, electrode cluster Cz/Pz) between smoking-related and neutral images, recorded with EEG during an image discrimination task before and after the hypnosis session. A greater pre-to-post reduction in cue reactivity is expected in the smoking cessation condition compared with the relaxation condition. 2. Daily cigarette consumption, recorded via daily diaries (REDCap) on three days before and three days after the session. A greater pre-to-post reduction is expected in the active condition. Statistical analysis: All endpoints are analysed in separate models. LPP cue reactivity: a difference score (LPP smoking - LPP neutral) is computed and entered into a mixed 2×2 ANOVA with the factors Condition (smoking cessation vs. relaxation) and Time (pre vs. post). The effect of interest is the Condition × Time interaction. If the interaction is significant, within-group pre–post comparisons are computed. Daily cigarette consumption: analysed with an appropriate generalised linear mixed model after assumption checks with fixed effects Condition, Time (pre/post) and Condition × Time, and a random intercept per participant. The effect of interest is the Condition × Time interaction. | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. P3 amplitude for object images (300–500 ms, Cz/Pz): index of attention allocation during stimulus evaluation. 2. LPP amplitude for object images (400–800 ms, Fz/Cz/Pz): index of emotional processing, as pictures remain visible throughout the response period. 3. Self-reported craving (QSU-Brief, both subscales: desire/intention to smoke; relief from negative affect), assessed before and after the intervention. Exploratory: Subjective hypnotic depth (ISHD, post-intervention) as a moderator of the intervention effects; physical nicotine dependence (FTND, baseline) as a covariate. Statistical analysis: Cue reactivity: a difference score (P3/LPP smoking - P3/LPP neutral) is computed and entered into a mixed 2×2 ANOVA with the factors Condition (smoking cessation vs. relaxation) and Time (pre vs. post). The effect of interest is the Condition × Time interaction. If the interaction is significant, within-group pre–post comparisons are computed. Craving (QSU-Brief): mixed 2×2 ANOVA (Condition × Time) computed separately for each subscale. Exploratory: ANCOVA models with FTND as a covariate and moderation analyses with ISHD. Assumptions (normality, homogeneity of variance) are checked; if violated, non-parametric or robust procedures are used. Additional confirmatory endpoints (Reported in separate publications): 1- Baseline beta cue reactivity (cross-sectional, pre-intervention data only, both arms pooled, N = 40). Event-related beta oscillations (13–30 Hz) are derived from the same EEG data. Primary (confirmatory): a within-subject difference in event-related beta activity between smoking-related and neutral images (cue reactivity). Secondary (exploratory): association of baseline beta cue reactivity with nicotine dependence/craving (FTND, daily cigarettes, QSUBrief). 2- Intervention effect on beta oscillations (pre + post data, both arms). Confirmatory hypothesis: in the active condition, the centre of event-related beta activity (peak fr | — |
Countries
Germany
Contacts
Public ContactStefan Debener
Carl von Ossietzky Universität Oldenburg Fakultät VI – Medizin und Gesundheitswissenschaften Department für Psychologie, Neuropsychology Lab
Outcome results
None listed