Effects of meditation


The psychological and physiological effects of meditation have been studied. In recent years, studies of meditation have increasingly involved the use of modern instruments, such as functional magnetic resonance imaging and electroencephalography, which are able to observe brain physiology and neural activity in living subjects, either during the act of meditation itself or before and after meditation. Correlations can thus be established between meditative practices and brain structure or function.
Since the 1950s, hundreds of studies on meditation have been conducted, but many of the early studies were flawed and thus yielded unreliable results. Another major review article also cautioned about possible misinformation and misinterpretation of data related to the subject. Contemporary studies have attempted to address many of these flaws with the hope of guiding current research into a more fruitful path.
However, the question of meditation's place in mental health care is far from settled, and there is no general consensus among experts. Though meditation is generally deemed useful, recent meta-analyses show small-to-moderate effect sizes. This means that the effect of meditation is roughly comparable to that of the standard self-care measures like sleep, exercise, nutrition, and social intercourse. Importantly, it has a worse safety profile than these standard measures. A recent meta-analysis also indicates that the increased mindfulness experienced by mental health patients may not be the result of explicit mindfulness interventions but more of an artefact of their mental health condition as it is equally experienced by the participants that were placed in the control condition. This raises further questions as to what exactly meditation does, if anything, that is significantly different from the heightened self-monitoring and self-care that follows in the wake of spontaneous recovery or from the positive effects of encouragement and care that are usually provided in ordinary healthcare settings. There also seems to be a critical moderation of the effects of meditation according to individual differences. In one meta-analysis from 2022, involving a total of 7782 participants, the researchers found that a higher baseline level of psychopathology was associated with deterioration in mental health after a meditation intervention and thus was contraindicated.

Effects of mindfulness meditation

A previous study commissioned by the American Agency for Healthcare Research and Quality found that meditation interventions reduce multiple negative dimensions of psychological stress. Other systematic reviews and meta-analyses show that mindfulness meditation has mental health benefits, including reductions in depression symptoms, improvements in mood, strengthening of stress-resilience, and attentional control. Mindfulness interventions also appear promising for managing depression in youth.
Mindfulness meditation is useful for managing stress, anxiety, and also appears to be effective in treating substance use disorders.
In 2016, Hilton and colleagues published a meta-analysis of 30 randomized controlled trials, found high-quality evidence for improvement in depressive symptoms.
Other reviews have concluded that mindfulness meditation can enhance the psychological functioning of breast cancer survivors, is effective for people with eating disorders and may also be effective in treating psychosis.
Studies have also shown that rumination and worry contribute to mental illnesses such as depression and anxiety, and mindfulness-based interventions are effective in the reduction of worry. Some studies suggest that mindfulness meditation contributes to a more coherent and healthy sense of self and identity when considering aspects such as a sense of responsibility, authenticity, compassion, self-acceptance, and character.

Brain mechanisms

The analgesic effect of mindfulness meditation may involve multiple brain mechanisms, of which chronic pain is shown to have a slight decrease when performing meditation. Current research demonstrates a lack of high-quality data to support a strong case for clinical prescription of meditation, however future research may further change our understanding of chronic pain treatment and mindfulness, but there are too few studies to allow conclusions about its effects on chronic pain.

Changes in the brain

Mindfulness meditation alters the brain, leading to a heightened ability to improve emotions. In an 8-week mindfulness meditation study, Gotink et al. results showed activity in the amygdala, insula, cingulate cortex, and hippocampus to decrease. Short-term brain changes such as these are correlated to effects seen in people who have practiced mindfulness over longer periods such as months or years. Another meta-analysis found preliminary evidence for effects in the prefrontal cortex and other brain regions associated with body awareness. However, these results should be interpreted with caution as funnel plots indicate that publication bias is an issue in meditation research. A 2016 review using 78 functional neuroimaging studies suggests that different meditation styles result in different brain activity. While other studies have found structural changes in the brain may occur, most studies have utilized weak methodology.

Attention and mindfulness

Attention networks and mindfulness meditation

Psychological and Buddhist conceptualizations of mindfulness both highlight awareness and attention training as key components in which levels of mindfulness can be cultivated with the practice of mindfulness meditation. Focused attention meditation and open monitoring meditation are distinct types of mindfulness meditation; FAM refers to the practice of intently maintaining focus on one object, whereas OMM is the progression of general awareness of one's surroundings while regulating thoughts. Some forms of Buddhist mindfulness meditation may lead to greater cognitive flexibility.
In an active randomized controlled study completed in 2019, participants who practiced mindfulness meditation demonstrated a greater improvement in awareness and attention than participants in the active control condition. Alpha wave neural oscillation power has been shown to be increased by mindfulness in both healthy subjects and patients.
Sustained attention
Tasks of sustained attention relate to vigilance and the preparedness that aids in completing a particular task goal. Psychological research into the relationship between mindfulness meditation and the sustained attention network has revealed the following:
  • In a continuous performance task an association was found between higher dispositional mindfulness and more stable maintenance of sustained attention.
  • In an electroencephalography study, the attentional blink effect was reduced, and P3b ERP amplitude decreased in a group of participants who completed a mindfulness retreat. The incidence of reduced attentional blink effect relates to an increase in the detectability of a second target.
  • A greater degree of attentional resources may also be reflected in faster response times in task performance, as was found for participants with higher levels of mindfulness experience.
    Selective attention
  • Selective attention, linked with the orientation network, selects the relevant stimuli to attend to.
  • Performance in the ability to limit attention to potential sensory inputs was found to be higher following the completion of an eight-week MBSR course, compared to a one-month retreat and control group. The ANT task is a general applicable task designed to test the three attention networks, in which participants are required to determine the direction of a central arrow on a computer screen. Efficiency in orienting that represent the capacity to attend to stimuli selectively was calculated by examining changes in the reaction time that accompanied cues indicating where the target occurred relative to the aid of no cues.
  • Meditation experience correlates negatively with reaction times on an Eriksen flanker task measuring responses to global and local figures. Similar findings have been observed for correlations between mindfulness experience and an orienting score of response times taken from Attention Network Task performance.
  • Participants who engaged in the Meditation Breath Attention Score exercise performed better on anagram tasks and reported greater focused attention on this task compared to those who did not undergo this exercise.
    Executive control attention
  • Executive control attention includes functions of inhibiting the conscious processing of distracting information. In the context of mindful meditation, distracting information relates to attention-grabbing mental events, such as thoughts related to the future or past.
  • More than one study has reported findings of a reduced Stroop effect following mindfulness meditation training. The Stroop effect indexes interference created by having words printed in a color different from the read semantic meaning, e.g., green printed in red. However, the findings for this task are not consistently found. For instance the MBSR may differ to how mindful one becomes relative to a person who is already high in trait mindfulness.
  • Using the Attention Network Task, a version of the Eriksen flanker task, it was found that error scores that indicate executive control performance were reduced in experienced meditators and following a brief five-session mindfulness training program.
  • A neuroimaging study supports behavioral research findings that higher levels of mindfulness are associated with greater proficiency in inhibiting distracting information. A greater activation of the rostral anterior cingulate cortex was shown for mindfulness meditators than matched controls.
  • Participants with at least 6 years of experience meditating performed better on the Stroop Test than participants without experience meditating. The group of meditators also had lower reaction times during this test than the group of non-meditators.
  • Following a Stroop test, reduced amplitude of the P300 ERP component was found for a meditation group relative to control participants. This was taken to signify that mindfulness meditation improves executive control functions of attention. An increased amplitude in the N2 ERP component was also observed in the mindfulness meditation group, which was thought to reflect more efficient perceptual discrimination in earlier stages of perceptual processing.