Table 1.

Example meta- analyses of DMHIs for diverse treatment targets and populations

Article	Number of studies included	Treatment target(s)	Population	Digital mental health intervention	Contrast	Effect size
Andrews et al., 2018 (REF.63)	53	Depression and anxiety	Adults	iCBT	iCBT vs treatment as usual	g = 0.38*
					iCBT vs waiting list control	g = 0.90*
					iCBT vs face- to- face CBT	g = 0.14
Guo et al., 2020 (REF.166)	20	Social anxiety disorder (SAD)	Adults	iCBT	iCBT vs control groups	g = −0.55*
					iCBT vs face- to- face CBT	g = −0.18
Soh et al., 2020 (REF.167)	33	Insomnia	Adults	iCBT	iCBT vs control groups	d = 0.392*
Wootten, 2016 (REF.168)	18	Obsessive- compulsive symptoms	Adults	Remote CBT (delivered by computer, telephone and videoconference)	Remote CBT vs control	g = 1.06*
					Remote CBT vs face- to- face CBT	g = −0.21
Cervin and Lundgren, 2021 (REF.169)	9	Anxiety disorders	Children and adolescents	Technology- delivered CBT (tCBT; delivered by Internet, app, mobile phone or tablet computer)	tCBT vs control	OR = 4.73*
Thompson et al., 2021 (REF.48)	25	Anxiety, depression, quality of life and psychological flexibility	Adults	iACT	iACT vs control groups on anxiety	g = 0.24*
					iACT vs control groups on depression	g = 0.38*
					iACT vs control groups on quality of life	g = 0.27*
					iACT vs control groups on psychological flexibility	g = 0.32*
Lindegaard et al., 2020 (REF.55)	7	Depression, anxiety and quality of life	Adults	iPDT	iPDT vs controls on depression (g = 0.46), anxiety (g = 0.20) and quality of life (g = 0.40)	g = 0.46*
					iPDT vs controls on anxiety	g = 0.20*
					iPDT versus controls on quality of life	g = 0.40*
Linardon et al., 2019 (REF.80)	66	Depression, anxiety, stress, quality of life	Adults	Other: mobile apps	Smartphone apps vs controls on depressive symptoms	g = 0.28*
					Smartphone apps vs controls on generalized anxiety	g = 0.30*
					Smartphone apps vs controls on stress	g = 0.35*
					Smartphone apps vs controls on quality of life	g = 0.35*
Linardon et al., 2020 (REF.170)	36	Eating disorders	Adolescents and adults	Other: Internet- based, app- based and CD- ROM- based interventions	Digital interventions vs control conditions in reducing established risk factors and symptoms in prevention- focused trials	g values range from 0.19* to 0.43*
					Digital interventions vs control conditions in reducing established risk factors and symptoms in treatment- focused trials	g values range from 0.29* to 0.69*

Hedge’s g effect sizes can be interpreted as 0.2 is a small effect, 0.5 is a medium effect and 0.8 is a large effect. Linardon et al.¹⁷⁰ presented meta- analytic results for 35 outcomes; for brevity, results are summarized in ranges. Cervin and Lundgren¹⁶⁹ presented an odds ratio (OR) rather than a Hedge’s g value in their published meta- analyses; the OR indicated that participants who received tCBT were approximately four times as likely as control participants to achieve remission from their primary anxiety disorder. CBT, cognitive behavioural therapy; DMHI, digital mental health intervention; iACT, Internet- based acceptance and commitment therapy; iCBT, Internet- based cognitive behavioural therapy; iPDT, Internet- based psychodynamic therapy.

^*Statistically significant result.