TABLE 1.

Baseline Characteristics of Marines Receiving Mindfulness Training (MT Group) or Training as Usual (Control Group)

Variable	Main Sample				fMRI Subsamplea
	MT Group	(N=147)	Control Group	(N=134)	MT Group	(N=19)	Control Group	(N=16)
	Mean	SD	Mean	SD	Mean	SD	Mean	SD
Age (years)	21.7	2.6	21.4	2.5	22.4	3.1	20.9	1.1
Military service (years)	2.7	2.0	2.9	2.2	3.8	3.0	2.5	1.1
Height (inches)	69.8	3.1	69.5	2.8	69.7	3.1	71.3	2.3
Weight (lb)	171.5	19.8	171.8	18.7	168.4	19.3	173.8	16.6
Physical fitness test
Pull-ups (number completed)	16.3	4.9	16.0	3.9	17.2	4.6	15.1	2.8
Sit-ups (number completed)	101.3	15.7	99.7	8.0	99.3	2.9	100.0	0
3-mile run (minutes)b	20.5	1.9	21.2	1.8	20.3	2.0	21.0	1.8
Combat Experiences Scale score	2.7	4.7	2.6	3.7	3.4	5.4	3.9	4.4
Pittsburgh Sleep Quality Index scorec	8.4	4.0	7.0	3.6	9.8	4.3	6.7	3.6
Response to Stressful Experiences Scale score	65.5	13.5	68.0	12.2	60.1	11.9	66.1	12.7
	N	%	N	%	N	%	N	%
White	103	70	77	61	12	63	11	69
Marriedd	20	14	37	29	1	5	7	44
Associate’s degree or higher	13	9	5	4	1	5	0	0
Military occupational specialty: rifleman	139	95	126	96	16	94	16	100
Previous IIT exposuree	56	36	68	53	8	47	10	63
Combat experience	49	34	61	47	7	37	10	63
Taking medication	8	5	13	10	3	18	2	13

^aFrom the original fMRI subsample of 20 Marines in each group, data from one Marine in the MT group and four in the control group were excluded from analyses because of excessive head-motion artifact at either the baseline or the follow-up assessment (at approximately 10 weeks).

^bSignificant difference between MT and control groups (p=0.003).

^cSignificant difference between MT and control groups (p=0.007) and between fMRI subgroups (p=0.03).

^dSignificant difference between MT and control groups (p=0.002) and between fMRI subgroups (p=0.01).

^eIIT=Infantry Immersion Trainer facility. Significant difference between MT and control groups (p=0.02).