Mindfulness meditation demonstrably reduces depressive symptoms, anxiety and the experience of pain with a small to moderate effect. It is a safe addition to standard care, but does not outperform medication or other evidence-based therapies.
Meditation, and mindfulness meditation in particular, has been studied most extensively for depression and anxiety. Multiple systematic reviews show that meditation reduces both complaints with a small to moderate effect. For depression, the effect size was approximately 0.30 after eight weeks and 0.23 after three to six months; for anxiety, these figures were 0.38 and 0.22 respectively. These improvements can persist for six months or longer in some people. (PMID 24395196, 31083878, 15256293)
Meditation also helps somewhat with the experience of chronic pain, with a similarly moderate effect (effect size ~0.33). Importantly, this concerns how pain is perceived, not its physical cause. The pain itself does not disappear as a result. (PMID 24395196)
For sleep, attention, positive mood, eating habits, weight and substance use, the evidence is currently weak or entirely absent. You should not attach strong expectations to meditation in these areas, even though a great deal of positive commentary circulates about them online. (PMID 24395196)
There is one randomised study showing that as little as 13 minutes per day over eight weeks improved attention, working memory and emotion regulation in beginners compared with a control group. After four weeks, no effect was yet visible. This is promising but still limited evidence. (PMID 30153464)
In people with Parkinson's disease, a study involving 159 participants showed that eight weeks of meditation reduced anxiety, motor symptoms and a blood inflammatory marker (interleukin-6). Meditation outperformed yoga on depression and maintained the improvements for longer. This suggests that meditation may also be useful for specific neurological conditions as a supplement to standard care. (PMID 40024243)
Meditation has not proven to be superior to other active treatments such as medication, physical exercise or behavioural therapy. It is a useful addition, but not a miracle cure. No negative effects have been reported in the available studies, although that does not mean risks can be entirely ruled out. The evidence on safety is limited. (PMID 24395196, 31083878)
Based on two large meta-analyses/systematic reviews (PMID 24395196 and 31083878), one early systematic review (PMID 15256293), one randomised study in beginners (PMID 30153464) and one randomised trial in Parkinson's patients (PMID 40024243). Effect sizes are small to moderate; many comparisons are with inactive control groups, not with other active therapies.