Yazdani 2010.

Study characteristics
Methods	RCT, Iran
Participants	76 nursing students Quote: "The study population included all male and female nursing students who were studying in Isfahan Nursing and Midwifery university in 2010‐2011, in the second and third years (third, fourth, fifth and sixth semesters). 72 [sic] students were randomly assigned to two groups using the list of students studying in the second and third year in 2010‐2011 and based on the odd and even numbers." (p. 210) "The groups were heterogeneous in terms of gender..." (p. 210)
Interventions	1) Experimental: Stress management training (n = 38). Quote: "[First group (n=38) trained stress management training program (8 two hours sessions, twice a week). And second group (n = 38) did not received [sic] training." (p. 210) The stress management program consisted of: information about stress, gradual muscle relaxation and its implementation with mental imagery, consequences and physical symptoms of stress, relaxation and imagery and training and diaphragm breathing practices, linking thoughts and emotions and familiarity with cognitive errors, discussion about relaxation exercises and replacement of logical thoughts and personal stress management program. 2) Control: no intervention (n = 38)
Outcomes	DASS‐42: Depression, Anxiety and Stress Scale
Identification
Notes	DASS‐stress included in analysis 2.1 and DASS‐depression in analysis 2.3.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Quote: "...students were randomly assigned to two groups using the list of students studying in the second and third year in 2010‐2011 and based on the odd and even numbers." (p. 210)
Allocation concealment (selection bias)	Unclear risk	Not reported if group allocation was concealed
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants not blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Participants were not blinded whereas outcomes are self‐reported.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	It is difficult to tell if some participants were lost to follow‐up or not as the authors give three separate numbers for the amount of participants. Quote: "This study was a parallel ‐group randomized quasi‐experimental trial...on 68 BSc nursing students.", " 72 students were randomly assigned..." and "Finally seventy‐six subjects elected among them." (p. 210)
Selective reporting (reporting bias)	Low risk	The study had only one outcome and its results are all reported
Other bias	Low risk	We did not find any indications of other sources of bias