Appendix Table 1.

Excluded Studies that Investigated Mindfulness-Based Interventions Shorter than 8 Weeks but that Entailed at Least 6 H of Training Time (n = 6)

Citation	Enrolled	Age (M)	% White	% Female	Completed	Design	Type of practice	Duration/delivery method	Control	Mindfulness measurement	Pain-related measurement	Results
Cathcart et al.32	58 community members with chronic tension-type headaches	∼45	Not found	62	42	2-arm RCT	Based on mindfulness-based stress reduction and mindfulness-based cognitive therapy	6, 2-h group sessions over 3 weeks	Waitlist	Five facet mindfulness questionnaire	Self-reported headache intensity, frequency, and duration over 2-weeks and measures of depression, anxiety, and stress	Mindfulness condition outperformed control on headache frequency (p = 0.04) and observed facet of mindfulness (p = 0.01).
Duncan et al.33	30 healthy pregnant women	Not found	59	100	29	2-arm RCT	Adapted from mindfulness-based stress reduction	2.5 days of intensive training (about 18 h total)	Standard childbirth education	Five facet mindfulness questionnaire	Pain catastrophizing, perceived labor pain, use of pain medication during labor, and depression	Mindfulness condition outperformed control on depression (p < 0.04).
Esch et al.34	32 healthy adults	∼26	Not found	∼75	31	2-arm RCT	Body scan, attention to breath and sensations, open monitoring, walking meditation	5, 1.5-h group sessions over five consecutive days	Passive control	Freiburg mindfulness inventory	Tourniquet test: pain tolerance	No significant between-group differences.
Kingston et al.35	45 undergrads	23	Not found	79	42	2-arm RCT	Body scan, mindfulness of breath, sounds, thoughts, and body sensations	6, 1-h group sessions over 3 weeks	Guided imagery	Kentucky inventory of mindfulness skills	Positive effect, negative effect, and CPT: tolerance and self-reported pain intensity (1–10 scale)	Mindfulness scores increased over the mindfulness intervention (p < 0.005). Mindfulness intervention outperformed control on pain tolerance (p = 0.042) and intensity (p = 0.047).
Su et al.36	18 adults with moderate or severe pain, and 16 adults with mild or no pain	39	Not found	73	34	Within-group	Based on mindfulness-based stress reduction	6 weekly 2.5-h sessions and 8-h session in fourth week	N/A	Kentucky inventory of mindfulness skills	Pain intensity and pain-related impairment	Significant improvements in mindfulness (p < 0.001), pain intensity (p = 0.005), and pain-related impairment (p = 0.016).
Tekur et al.37	91 patients with chronic low-back pain	∼48	Not found	46	80	2-arm RCT	Mindful yoga	1-week intensive residential yoga program (about 119 h total)	Exercise, education, breathing technique	Not found	Pain intensity, pain-related disability, and spinal flexibility	Mindfulness condition outperformed control on pain intensity (p < 0.001), pain-related disability (p < 0.001), and spinal flexibility (ps ranged from 0.002 to 0.059).

RCT, randomized controlled trial; CPT, cold-pressor task.