58% of 96 participants reported at least one meditation-related adverse effect, ranging from perpetual hypersensitivity to nightmares.

Evidence

Making mindfulness meditation more helpful starts with understanding … (Brown University)

corroborated: 2 independent passages support this claim
XREF: connects to: Mindlessness leads to panic and detrimental behavior. — Dan Harris, 10 percent Happier, 40; Recent studies reveal that 25–87% of those who engage in meditation report adverse effects, with 3–37% experiencing functional impairment. — Adverse effects of meditation and mindfulness in clinical practice; At least 25% of regular meditators have experienced adverse effects from mindfulness. — How too much mindfulness can spike anxiety (+3 more)

At least 25% of regular meditators have experienced adverse effects from mindfulness. (similarity 0.94)
Recent studies reveal that 25–87% of those who engage in meditation report adverse effects, with 3–37% experiencing functional impairment. (similarity 0.93)
The most common adverse effects are anxiety and depression, followed by psychotic or delusional symptoms and dissociation. (similarity 0.89)
Studies have described adverse events such as anxiety, pain, and psychosis associated with mindfulness meditation. (similarity 0.89)
Meditation and mindfulness, widely perceived as stress-reduction techniques, can also have adverse effects. (similarity 0.88)
About 30% of meditators experienced challenging or distressing effects, and 9% reported functional impairment. (similarity 0.87)
Anxiety, traumatic re-experiencing, and emotional sensitivity were the most common MRAE; 10.6% reported some functional impairment. (similarity 0.86)
Meditation practice in MBPs is associated with transient distress and negative impacts at similar rates to other psychological treatments. (similarity 0.85)
A new harm monitoring study investigates the adverse effects of mindfulness-based practices. (similarity 0.83)
Harmful psychological treatments are damaging and cause worse outcomes than would have occurred without treatment. (similarity 0.80)
The Varieties of Contemplative Experience study identified more than 50 types of meditation-related challenging experiences across seven domains. (similarity 0.78)