According to research are there specific Practices associated with a greater risk of someone experiencing an adverse effect? Yes!

• Any practice longer than 30 mins.
• Insistence on immobility during long practices.
• Body Scan and Breath based practices.
• Those in which the focus is on 'no-self', dissolution of the ego, and those with an emphasis on exploration of 'who is this observer/where is this observer' and who is this self.
• Practices that insist on use of decentred language, avoiding use of me, mine, your etc and replacing this with 'the' . e.g. 'the body' replacing 'your body' in practice guidance.

Are there any circumstances in which participants are at higher risk?

Research indicates that certain forms of retreats and practices within them are high risk.

• Silent retreats in which connection with other's is banned. One of the ways humans naturally regulate emotion is through co-regulation with others. On some retreats one is not supposed to even make eye contact with another person. If someone is experiencing high emotional arousal with no opportunity for co regulation with others this can lead to severe adverse effects.
• Food restriction. Again research indicates that a sudden change in eating habits (meal frequency, change from meat eating to vegan, and restrictive calorie intake) can precipitate adverse effects. Nutrient dense food such as meat is very grounding to the human organism so if someone becomes ungrounded in practice, eating nutrient dense food can help. In retreats where meat is not served this grounding does not happen. In addition many retreat traditions are inflexible in permitting adaptations, further exacerbating the situation.
• Some lineage traditions are very inflexible in their interpretation of and adaptation too adverse effects, insisting on a POV that is known to be risky once an adverse effect has occurred. Telling people that what they are experiencing is normal, refusing to make adaptations for people who are suffering, and giving unhelpful advice such as to keep up with or even increase the very practices that are causing distress. This then becomes harm and/or trauma.

More generally teachers should pay attention to the environment in which they are teaching. The use of church halls, Buddhist or other centres based on specific religion or life path system should be avoided unless it is clear one is teaching from/within such a tradition or lineage. Teachers offering secular meditation need to avoid such venues completely and offer sessions in a neutral space free of icons, images or materials to the contrary. 

Teachers need to understand the lineage of the programme or system they are offering in order to avoid moral injury. MBSR and all courses and curriculums based on it are in fact founded on transmitting Buddhist dharma.