 The psychologist Thomas Joiner argues that modern mindfulness meditation has been "corrupted" for commercial gain by self-help celebrities, and suggests that it encourages unhealthy narcissistic and self-obsessed mindsets.Meditation has been correlated with unpleasant experiences in some people.In one study, published in 2019, of 1,232 regular meditators with at least two months of meditation experience, about a quarter reported having had particularly unpleasant meditation-related experiences (such as anxiety, fear, distorted emotions or thoughts, altered sense of self or the world), which they thought may have been caused by their meditation practice.