The episode explores meditation-related difficulties that are often overlooked, particularly during intensive retreats or prolonged practice. Reported problems include anxiety, insomnia, dissociation, altered motivation, extreme states of arousal and, in some cases, mania or psychosis. Some people experience symptoms that continue for years or return when they resume intensive meditation. The discussion also shows that these concerns are not entirely new: Buddhist traditions have long recognised that contemplative practice can produce challenging experiences. Researchers describe several possible explanations, including meditation’s effects on attention and arousal systems, with risk potentially increasing according to the intensity or “dose” of practice. They assess whether meditation caused a person’s symptoms by examining repeated patterns, ruling out alternative explanations and applying established causal criteria. The episode stresses that adverse reactions cannot simply be blamed on personal weakness or poor technique. Although previous psychiatric or trauma histories may increase vulnerability, serious effects can also affect experienced practitioners. It concludes by questioning whether the evidence is strong enough to support widespread mindfulness programs, particularly in schools.