Modality- and sequence-specific effects of guided imagery on stress and neuroendocrine markers in young adults: A...

Guided mental imagery interventions are increasingly used for stress reduction, but evidence comparing the effects of different imagery modalities remains limited. This pilot study examined modality-specific and sequence-dependent effects of calming and achievement imagery on perceived stress and neuroendocrine markers.

Thirty-two male adults (18-25 years) completed a 5-day pilot randomized, counterbalanced crossover study. Participants were assigned to calming-then-achievement (CAG, n = 13), achievement-then-calming (ACG, n = 12), or a no-intervention control group (CG, n = 7). Biomarkers were assessed on Days 1, 3, and 5 in active groups and Days 1 and 5 in CG; perceived stress was assessed on Days 1 and 5.

Serotonin was significantly higher following achievement than calming imagery (calming - achievement: -66.5 ng/mL, 95% CI -123.2 to -9.8; p = .019; partial η² = .113), with a significant sequence effect (p = .014). Cortisol and β-endorphin showed no modality, period, or sequence effects. β-Endorphin increased over time (p < .001); cortisol showed no significant time, group, or interaction effects. Serotonin showed significant time, group, and time-by-group effects (all p < .001), including a marked increase in the untreated control group by Day 5. No significant effect of sequence or modality was found on perceived stress.

These preliminary, hypothesis-generating results suggest achievement imagery may selectively engage serotonergic activity, while both modalities similarly engage the endogenous opioid system; no effect was found on cortisol or perceived stress. Given the pilot design, small sample, multiple outcomes, and the serotonin increase in the untreated control group, findings should be confirmed in adequately powered randomized trials.