RecruitingPhase 2Combination productMindfulness-based Psilocybin Therapy for PTSDThe goal of this study is to learn how psilocybin delivered with mindfulness-based therapy may help symptoms of posttraumatic stress disorder (PTSD). This is an assessor-blinded, randomized, controlled study in participants with PTSD. The study will investigate the changes in brain activity, connectivity, and microstructural neuroplasticity assessed using EEG/EMG and multimodal MRI measures after administration of one oral dose of psilocybin, accompanied either with standard "psychological support" only; or with standard support plus Mindfulness-based Cognitive Therapy (MBCT).