IntroductionFatigue is a frequent, disabling, and difficult to treat symptom in neurological disease and in other stress-related conditions; Integrated Imaginative Distention (IID) is a therapy combining muscular and imaginative relaxation, feasible also in disabled subjects; the DIMMI SI trial was planned to evaluate IID efficacy on fatigue.MethodsThe design was a parallel, randomised 1:1 (intervention:waiting list), controlled, open-label trial. Participants were persons with multiple sclerosis (pwMS), persons with insomnia (pwINS), and health professionals (HP) as conditions related to fatigue and stress. The primary outcome was the post-intervention change of fatigue; secondary outcomes were changes in insomnia, stress, and quality of life (QoL). Eight IID weekly training group sessions were delivered by a skilled psychotherapist. The study lasted 12 months.ResultsOne hundred and forty-four subjects were enrolled, 48 for each condition. The mean change in Modified Fatigue Impact Scale (MFIS) score among exposed was 7.7 [95% CI 1.1, 14.4] (P = 0.023) in pwMS; 7.1 [1.9, 12.3] (P = 0.007) among pwINS, and 11.3 [4.3, 18.2] among HP (P = 0.002). At the last follow-up, the benefit was confirmed on physical fatigue for pwMS, on total fatigue for pwINS and HP.ConclusionsDIMMI SI is the first randomized controlled trial evaluating the efficacy of IID on fatigue. IID resulted a complementary intervention to reduce fatigue in stress-related conditions, in both health and disease status. NCT02290990ClinicalTrials.gov.Electronic supplementary materialThe online version of this article (doi:10.1007/s40120-017-0081-9) contains supplementary material, which is available to authorized users.