. 2023 Apr 12;23:150. doi: 10.1186/s12883-023-03176-9

Table 2.

Overview of the GRADE approach

Outcomes	(1)	(2)	(3)	(4)	(5)	Studies	N° of participants (Diseases vs Health controls) / N° of studies		^*Effect size	Quality of the evidence
Parkinson’s disease
Depression	Ns	Ns	S^C	Ns	Ns	Shalash et al. 2020 [29] Xia et al. 2020 [30]	157	189	SMD = 0.40 (moderate effect) 95% CI = 0.02 to 0.77 p = 0.04 I² = 44% (moderate heterogeneity)	⨁⨁⨁◯ Very low
Depression	Ns	Ns	S^C	Ns	Ns	Shalash et al. 2020 [29] Xia et al. 2020 [30]	(two studies)			⨁⨁⨁◯ Very low
Stress	Ns	Ns	S^C	Ns	Ns	Blakemore et al. 2021 [32] Shalash et al. 2020 [29]	187	71	SMD = 0.60 (moderate effect) 95% CI = 0.32 to 0.87 p < 0.0001 I² = 0% (low heterogeneity)	⨁⨁⨁◯ Very low
Stress	Ns	Ns	S^C	Ns	Ns	Blakemore et al. 2021 [32] Shalash et al. 2020 [29]	(two studies)			⨁⨁⨁◯ Very low
Anxiety	S^A	S^B	S^C	Ns	Ns	Salari et al. 2020 [28] Shalash et al. 2020 [29] Xia et al. 2020 [30]	294	631	SMD = 0.64 (moderate effect) 95% CI = -0.08 to 1.36 p = 0.08 I² = 95% (high heterogeneity)	⨁◯◯◯ Very low
Anxiety	S^A	S^B	S^C	Ns	Ns		(three studies)			⨁◯◯◯ Very low
Multiple Sclerosis
Depression	Ns	Ns	S^C	Ns	Ns	Yeni, Tulek and Terzi, 2022 [45] Shaygannejad, Afshari-Safavi and Hatef, 2021 [41] Motolese et al. 2020 [35] Stojanov et al. 2020 [36] Talaat et al. 2020 [37]	582	785	SMD = 0.73 (moderate effect) 95% CI = 0.20 to 1.26 p = 0.007 I² = 95% (high heterogeneity)	⨁⨁⨁◯ Very Low
Depression	Ns	Ns	S^C	Ns	Ns		(five studies)			⨁⨁⨁◯ Very Low
Stress	Ns	Ns	Ns	Ns	Ns	Shaygannejad, Afshari-Safavi and Hatef, 2021 [41] Talaat et al. 2020 [37]	338	334	SMD = 0.69 (moderate effect) 95% CI = 0.07 to 1.31 p = 0.03 I² = 93% (high heterogeneity)	⨁⨁⨁⨁ Low
Stress	Ns	Ns	Ns	Ns	Ns		(two studies)			⨁⨁⨁⨁ Low
Quality of life	Ns	Ns	S^C	Ns	Ns	Goverover et al. 2022 [43] Costabile et al. 2021 [39]	566	443	SMD = 0.77 (moderate effect) 95% CI = 0.21 to 1.32 p = 0.006 I² = 89% (high heterogeneity)	⨁⨁⨁◯ Very Low
Quality of life	Ns	Ns	S^C	Ns	Ns	Goverover et al. 2022 [43] Costabile et al. 2021 [39]	(two studies)			⨁⨁⨁◯ Very Low
Anxiety	Ns	Ns	S^C	Ns	Ns	Yeni, Tulek and Terzi, 2022 [45] Shaygannejad, Afshari-Safavi and Hatef, 2021 [41] Motolese et al. 2020 [35] Stojanov et al. 2020 [36] Talaat et al. 2020 [37]	582	785	SMD = 0.53 (moderate effect) 95% CI = -0.01 to 1.06 p = 0.05 I² = 95% (high heterogeneity)	⨁⨁⨁◯ Very Low
Anxiety	Ns	Ns	S^C	Ns	Ns		(five studies)			⨁⨁⨁◯ Very Low
Sleep quality	Ns	Ns	Ns	Ns	Ns	Yeni, Tulek and Terzi, 2022 [45] Stojanov et al. 2021 [42] Motolese et al. 2020 [35]	216	397	SMD = 0.80 (large effect) 95% CI = -0.23 to 1.82 p = 0.13 I² = 97% (high heterogeneity)	⨁⨁⨁⨁ Low
Sleep quality	Ns	Ns	Ns	Ns	Ns		(three studies)			⨁⨁⨁⨁ Low

SMD standardized mean differences, 95% CI 95% of confidence interval, I2 consistency between the studies

(1) Limitations (risk of bias); (2) Inconsistency; (3) Indirectness; (4) Imprecision; (5) Publication bias; (Ns) No serious; (S) Serious; A Downgrading due to < 75% of the studies presented low risk of bias; B Downgrading due to different directions towards the results found; C Downgrading due to heterogeneity of the scales for evaluating measures of results; D Downgrading due to was sparse data with less than 200 individuals per comparison; E Downgrading if > 50% of the studies are from the same research team

^*Cohen's criteria: small effect (< 0.20), moderate effect (between 0.21 and 0.79) or large effect (> 0.80)