Table 2.

Study characteristics grouped by control type

Authors, year	Control type	Population	Mindfulness na	Control nb	Mindfulness intervention	Mindfulness intervention delivery mode	Comparison intervention	Comparison intervention delivery mode	Intervention duration	Intervention hoursc	Scale /V0 meand
Hesser et al., 2012	SAC	Tinnitus	35	32	ACT	Web-based App	CBT	Web-based App	8 weeks	16	ISI 13.91
Low et al., 2020	SAC	Insomnia	12	11	MM	Mobile App	Progressive muscle relaxation	Mobile App	40 or 60 dayse	6.67 or 10	ISI 13.61
Mak et al., 2017	SAC	Young adults	1041	1040	MM	Web-based App	CBT	Web-based App	8 weeks	5	MOS-SS 26.49
Boettcher et al., 2014	NSAC	Anxiety disorders	45	46	MM	Web-based App	Discussion forum	Web-based App	8 weeks	16	ISI 11.74
Hesser et al., 2012	NSAC	Tinnitus	35	32	ACT	Web-based App	Discussion forum	Web-based App	8 weeks	16	ISI 13.49
Messer et al., 2019	UCC	Cancer survivors	11f	10f	MBSR	Web-based App	Usual care	NA	6 weeks	8	PSQI 11.57
Simister et al., 2018	UCC	Fibromyalgia	33	34	ACT	Web-based App	Usual care	NA	8 weeks	NR	PSQI 12.97
Chapoutot et al., 2020	Waitlist	Insomnia with hypnotic dependence	16	16	ACT-enhanced CBT	Video-conference	Waitlist	NA	8 weeks	4	PSQI 14.80
Lappalainen et al., 2019	Waitlist	Insomnia	43	43	ACT	Web-based App	Waitlist	NA	6 weeks	NR	ISI 16.96
Nissen et al., 2020	Waitlist	Cancer survivors	104	46	MBCT	Web-based App	Waitlist	NA	8 weeks	NR	ISI 11.73
Querstret et al., 2017	Waitlist	Working adults	63	64	MM	Web-based App	Waitlist	NA	4 weeks	NR	PSQI 11.26

ACT acceptance and commitment therapy, CBT cognitive behavioral therapy, ISI Insomnia Severity Index, MBCT mindfulness-based cognitive therapy, MBSR mindfulness-based stress reduction, MM mindfulness meditation, MOS-SS Medical Outcomes Study-Sleep Scale, NA not applicable, NR not reported, NSAC nonspecific active control, PSQI Pittsburgh Sleep Quality Index, SAC specific active control, UCC usual care control

^aMindfulness sample size is reported as participants initially randomized to the intervention group

^bControl sample size is reported as participants initially randomized to the control group

^cMindfulness hours are reported as expected hours per intervention, excluding home practice

^dThe V0 sleep quality mean score (i.e., baseline weighted average) was used to determine if each study cohort had clinically relevant sleep disturbance based on established cut-off scores

^eDue to time constraints, some participants were asked to complete 40 days of mindfulness meditation instead of 60 days; both groups were combined in the analysis.-

^fTwo participants dropped out of the study after randomization. The study did not report the two participants’ group affiliation; thus, the sample sizes reflect the number of participants who completed the intervention