Table 2.

Linear mixed effect model of main effects and interaction between recommended use and time for Happify Scale scores.

Predictor		Main effects–only model		Interaction model
		Model estimate (95% CI)	P value	Model estimate (95% CI)	P value
Intercepta		60.474 (57.721 to 63.226)	<.001	61.037 (58.277 to 63.796)	<.001
Recommended use		9.071 (7.563 to 10.578)	<.001	7.636 (6.053 to 9.219)	<.001
Time from baseline (days)		0.049 (0.041 to 0.057)	<.001	0.03 (0.021 to 0.04)	<.001
Total chronic conditions		–2.168 (–2.693 to –1.642)	<.001	–2.168 (–2.694 to –1.643)	<.001
GAD-2b score at baseline		–5.267 (–5.657 to –4.877)	<.001	–5.26 (–5.65 to –4.871)	<.001
Female gender		0.676 (–1.001 to 2.354)	.43	0.691 (–0.987 to 2.368)	.42
Age group (years)
	18-24	–0.512 (–4.714 to 3.69)	.81	–0.509 (–4.709 to 3.692)	.81
	25-34	–1.354 (–3.727 to 1.019)	.26	–1.366 (–3.739 to 1.007)	.26
	35-44	–0.759 (–2.739 to 1.221)	.45	–0.768 (–2.747 to 1.212)	.45
	45-54	-c	-c	-c	-c
	55-64	1.131 (–0.769 to 3.031)	.24	1.131 (–0.769 to 3.031)	.24
User is in a relationship		6.093 (4.39 to 7.797)	<.001	6.106 (4.403 to 7.809)	<.001
User has at least one minor child		–1.035 (–2.755 to 0.684)	.24	–1.024 (–2.743 to 0.695)	.24
Recommended use by time from baseline		N/Ad	N/A	0.047 (0.032 to 0.063)	<.001

^aRepresents the score for a male user aged 45-54 years at baseline with 0 chronic conditions, no anxiety symptoms, not in a relationship, with no children, and who did not meet the recommended use of an average of 2 activities per week.

^bGAD-2: Generalized Anxiety Disorder-2.

^cReference group.

^dN/A: not applicable to the first model.