Table 3.

Effect size of mindfulness intervention in improving loneliness.

Trials	Scale	Range of score of scale	Mean difference (95% CI)
Creswell et al. (2012)	UCLA-R	20–80	−7.30 (−13.81, −0.79)*
Jazaieri et al. (2012)	UCLA-8	0–100~	−0.79 (−3.74, 2.16)
Dodds et al. (2015)	UCLA-R	20–80	−2.40 (−12.01, 7.21)
Mascaro et al. (2018)	UCLA-R	20–80	−6.50 (−10.20, −2.80)*
Zhang et al. (2018)	Indigenous loneliness test	NA (unable to retrieve article)	−4.77 (−8.60, −0.94)*
Lee et al. (2019)	Loneliness score as part of mental health test	1–5 (Likert scale)	0.03 (−0.70, 0.76)∧
			−0.17 (−0.87, 0.53)
Lindsay et al. (2019)	UCLA-R	20–80	1.60 (−3.11, 6.29)
Pandya (2019)@	De Jong Gierveld Loneliness Scale	5–35	2.41 (2.20, 2.62)*

^@Lower score indicated more loneliness; while for all other trials, higher score indicated more loneliness.

^~Obtained from original literature of the scale (Hays and DiMatteo, 1987).

^*Statistically significant result.

^∧Conservative estimate from Lee et al. (2019).