Participants and setting
DISEASES, DISORDERS
Study setting was the support organization for vulnerable individuals in Tehran, Iran, and study population consisted of all single-parent adolescent girls who referred to the study setting. Participants were 88 girls who were willing to participate in the study and met the following eligibility criteria: age 13–18 years, having just one parent, and no self-report history of psychological disorders or specific diseases. More than two absences from the intervention sessions were the exclusion criterion. It should be noted that ethical approval was given by the organizational ethics committee of the nursing-midwifery and rehabilitation faculty and participants entered the study voluntarily and completed the informed consent form. Participants were randomly allocated to a control and an intervention group through block randomization and using an online randomization module (Sample size was calculated using the results of a study into the effects of education for student health ambassadors on HPL among adolescent girls. Accordingly, with a confidence level of 0.85, a power of 0.80, a standard deviation of 15 for the HPL score, and at least 10 score increase in the mean score of HPL after VL to be considered significant [Sample size calculation formula