Table 3.
Effect sizes from included studies by outcome domain.
| Meta-analysis | Effect size type | Human-supported | Not supported | Significant difference | |||||||||||||
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Effect size | CI | Effect size | CI | Yes or no | Direction | ||||||||||
| Anxiety | |||||||||||||||||
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Victorson et al [73], 2020 | Effect size differencesa | Mean −0.07 (SD 0.88) | —b | Mean −0.14 (SD 0.47) | — | No | No difference; not significant | |||||||||
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Sherifali et al [45], 2018 | SMDc | −0.36 | −0.66 to −0.07 | −0.42 | −0.65 to −0.19 | Yes | Unsupported significantly; more effective | |||||||||
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Phillips et al [44], 2019 | Hedges g | 0.48 | 0.16 to 0.80 | 0.26 | 0.10 to 0.41 | Yes | Guided significantly; more effective | |||||||||
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Thompson et al [42], 2021 | Hedges g | 0.28 | 0.18 to 0.38 | 0.16 | −0.10 to 0.42 | No | Guided slightly more effective; not significant | |||||||||
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Kampmann et al [64], 2016 | Hedges g | 0.87 | 0.72 to 1.02 | 0.78 | 0.50 to 1.05 | No | Guided slightly more effective; not significant | |||||||||
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Kampmann et al [64], 2016 | Hedges g | 0.47 | 0.15 to 0.78 | 0.19 | −0.08 to 0.46 | No | Guided slightly more effective; not significant | |||||||||
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Linardon et al [7], 2019 | Hedges g | 0.53 | 0.36 to 0.70 | 0.21 | 0.12 to 0.30 | Yes | Guided significantly; more effective | |||||||||
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Spijkerman et al [69], 2016 | Hedges g | 0.26 | 0.02 to 0.50 | 0.19 | −0.06 to 0.43 | No | Guided slightly more effective; not significant | |||||||||
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Harrer et al [63], 2018 | Hedges g | 0.27 | 0.02 to 0.52 | 0.25 | 0.02 to 0.49 | No | Guided slightly more effective; not significant | |||||||||
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Domhardt et al [4], 2019 | SMD | −0.39 | −0.59 to −0.18 | — | — | Yes | Guided significantly; more effective | |||||||||
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Păsărelu et al [38], 2017 | Hedges g | 0.87 (clinical psychologist); 0.76 (supervised students) | 0.48 to 1.26; 0.56 to 0.96 | 0.54 | — | Yes | Guided significantly; more effective | |||||||||
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Mehta et al [46], 2019 | Cohen d | 0.54 (SE 0.08) | — | Mean 0.57 (SE 0.12) | — | No | Unsupported slightly more effective; not significant | |||||||||
| Depression | |||||||||||||||||
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Victorson et al [73], 2020 | Effect size differences | Mean −0.12 (SD 0.93) | — | Mean−0.46 (SD 0.79) | — | No | No difference; not significant | |||||||||
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Richards and Richardson [40], 2012 | Cohen d | 0.78 | −0.92 to −0.64 | 0.36 | −0.61 to −0.10 | Yes | Guided significantly; more effective | |||||||||
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Sherifali et al [45], 2018 | SMD | −0.34 | −0.63 to −0.05 | −0.31 | −0.50 to −0.11 | Yes | Guided significantly; more effective | |||||||||
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Phillips et al [44], 2019 | Hedges g | 0.48 | 0.33 to 0.63 | 0.23 | 0.08 to 0.37 | Yes | Guided significantly; more effective | |||||||||
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Thompson et al [42], 2021 | Hedges g | 0.45 | 0.34 to 0.56 | 0.14 | −0.022 to 0.29 | Yes | Guided significantly; more effective | |||||||||
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Firth et al [60], 2017 | Hedges g | 0.137 | −0.08 to 0.35 | 0.465 | 0.30 to 0.63 | Yes | Unsupported significantly; more effective | |||||||||
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Li et al [66], 2014 | Cohen d | −0.44 | −0.73 to −0.15 | −0.54 | −0.86 to −0.21 | Yes | Unsupported significantly; more effective | |||||||||
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Linardon et al [7], 2019 | Hedges g | 0.48 | 0.34 to 0.62 | 0.23 | 0.15 to 0.31 | Yes | Guided significantly; more effective | |||||||||
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Cheng et al [47], 2020 | Cohen d | 0.22 | — | 0.27 | — | No | Unsupported slightly more effective; not significant | |||||||||
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Cowpertwait and Clarke [59], 2013 | Hedges g | 0.48 | 0.39 to 0.57 | 0.32 | 0.23 to 0.41 | Yes | Guided significantly; more effective | |||||||||
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Spijkerman et al [69], 2016 | Hedges g | 0.29 | 0.06 to 0.53 | 0.29 | 0.03 to 0.55 | No | No difference, not significant | |||||||||
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Sijbrandij et al [67], 2016 | Hedges g | 0.66 | 0.36 to 0.96 | 0.55 | 0.12 to 0.98 | No | Guided slightly more effective; not significant | |||||||||
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Harrer et al [63], 2018 | Hedges g | 0.28 | −0.02 to 0.57 | 0.15 | 0.06 to 0.25 | No | Guided slightly more effective; not significant | |||||||||
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Simmonds-Buckley et al [68], 2020 | Hedges g | 0.61 (predominantly therapist delivered); 0.39 (minimal contact) | —; 0.16 to 0.62 | 0.30 | 0.15 to 0.45 | No | Guided slightly more effective; not significant | |||||||||
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Mehta et al [46], 2019 | Cohen d | 0.64 (SE 0.15) | — | Mean 0.45 (SE 0.18) | — | Yes | Guided significantly; more effective | |||||||||
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Twomey et al [71], 2020 | Hedges g | 0.57 | 0.36 to 0.78 | 0.47 | 0.32 to 0.62 | No | Guided slightly more effective; not significant | |||||||||
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Wright et al [43], 2019 | Hedges g | 0.673 | 0.546 to 0.801 | 0.239 | 0.115 to 0.364 | Yes | Guided significantly; more effective | |||||||||
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Pang et al [41], 2021 | Hedges g | −0.60 (therapist); −0.27 (web-based health care provider) | −0.81 to −0.38; −0.58 to 0.05 | −0.17 | −0.40 to 0.06 | Yes | Guided significantly; more effective | |||||||||
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Sztein et al [6], 2018 | SMD | 0.73 | 0.58 to 0.87 | 0.79 | 0.55 to 1.03 | No | No statistically significant difference | |||||||||
| PTSDd | |||||||||||||||||
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Kuester et al [65], 2016 | Hedges g | 0.8 | 0.62 to 0.98 | 0.54 | 0.22 to 0.86 | No | Guided slightly more effective; not significant | |||||||||
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Sijbrandij et al [67], 2016 | Hedges g | 0.89 | 0.70 to 1.08 | 0.5 | 0.22 to 0.78 | Yes | Guided significantly; more effective | |||||||||
| Stress | |||||||||||||||||
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Spijkerman et al [69], 2016 | Hedges g | 0.89 | 0.65 to 1.12 | 0.19 | −0.01 to 0.38 | Yes | Guided significantly; more effective | |||||||||
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Victorson et al [73], 2020 | Effect size differences | Mean −0.20 (SD 0.49) | — | Mean −1.63 (SD 1.8) | — | Yes | Unsupported significantly; more effective | |||||||||
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Phillips et al [44], 2019 | Hedges g | 0.76 | 0.44 to 1.08 | 0.38 | 0.19 to 0.56 | Yes | Guided significantly; more effective | |||||||||
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Conley et al [58], 2016 | Hedges g | 0.55 | 0.37 to 0.72 | 0.28 | 0.14 to 0.40 | Yes | Guided significantly; more effective | |||||||||
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Heber et al [5], 2017 | Cohen d | 0.64 | (0.50 to 0.79) | 0.33 | (0.20 to 0.46) | Yes | Guided significantly; more effective | |||||||||
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Grist et al [62], 2019 | Hedges g | 0.87 (minimal contact therapy);0.81 (predominantly self-help) | 0.68 to 1.06; −0.68 to −2.31 | 0.24 | 0.10 to 0.38 | Yes | Guided significantly; more effective | |||||||||
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Simmonds-Buckley et al [68], 2020 | Hedges g | 0.60 (minimal therapist contact); 0.47 (predominantly self-help) | 0.36 to 0.83; 0.11 to 0.83) | 0.23 | 0.09 to 0.36 | Yes | Guided significantly; more effective | |||||||||
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Carolan et al [57], 2017 | Hedges g | 0.39 | 0.18 to 0.61 | 0.34 | 0.16 to 0.53 | No | Guided slightly more effective; not significant | |||||||||
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Stratton et al [70], 2017 | Hedges g | 0.27 | — | 0.22 | — | No | Guided slightly more effective; not significant | |||||||||
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Versluis et al [72], 2016 | Hedges g | 0.73 (mental health provider); 0.38 (DMHI + care as usual) | 0.57 to 0.88; 0.11 to 0.64 | 0.45 | 0.22 to 0.69 | Yes | Guided significantly; more effective | |||||||||
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Fu et al [61], 2020 | Hedges g | 0.61 | 0.43 to 0.78 | 0.6 | 0.35 to 0.86 | No | Guided slightly more effective; not significant | |||||||||
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Leung et ale [52], 2022 | Hedges g | −0.17 | −0.23 to 0.11 | — | — | Yes | Guided significantly; more effective | |||||||||
aVictorson et al [73] reported differences in effect sizes for supported versus unsupported interventions.
bNot available.
cSMD: standardized mean difference.
dPTSD: posttraumatic stress disorder.
ePosttreatment SMD effect size overall comparison.