A total of 32 mothers who met the inclusion criteria comprised the intervention group and received a total of eight laughter yoga sessions. The laughter yoga intervention was delivered by a researcher certified as a laughter yoga instructor. The intervention protocol was developed within a structured program framework, with each session conducted according to standardized and pre-established guidelines. The laughter yoga sessions encompassed clapping and warm-up exercises, diaphragmatic breathing techniques, incorporation of elements fostering childlike joy and playfulness, as well as guided laughter exercises.

Thirty-two mothers who met the inclusion criteria constituted the control group. No intervention was administered to the control group. Since the laughter yoga sessions were conducted in a closed environment, the risk of transmission through sound and visual contact was prevented.

Laughter yoga is a mind-body practice that combines unconditional laughter with yogic breathing techniques (known as pranayama). Developed by Dr. Madan Kataria in 1995, the practice is based on the principle that voluntary laughter can provide similar physiological and psychological benefits as spontaneous laughter. It is typically conducted in group sessions involving eye contact, playful behavior, and laughter exercises, which aim to reduce stress, enhance mood, and promote overall well-being.

The scale uses a 7-point Likert-type rating system and consists of 17 items. The total score ranges from a minimum of 17 to a maximum of 119. Higher scores indicate higher levels of self-efficacy. The Cronbach's Alpha internal consistency coefficient of the scale was found to be 0.95.

When examining the findings related to the reliability and validity of the scale, it was found-contrary to the original version-that the scale has a unidimensional structure. It has been determined to be a valid and reliable tool for assessing the parental self-efficacy levels of mothers and fathers of children with moderate to severe intellectual disabilities in Turkey.

The items are rated on a 4-point scale based on how frequently participants experience the emotions described in the items, ranging from 0 ("never") to 4 ("every day"). The scale consists of two subdimensions: Emotional Exhaustion and Personal Accomplishment.

The Emotional Exhaustion subscale includes 13 items and has a reliability coefficient of 0.80. Higher average scores on this subscale indicate greater levels of burnout. The Personal Accomplishment subscale consists of 8 items, also with a reliability coefficient of 0.80. Unlike the Emotional Exhaustion subscale, lower average scores on the Personal Accomplishment subscale indicate a higher level of experienced burnout.

The internal consistency coefficient of the scale was calculated as 0.84, and the test-retest reliability coefficient was found to be 0.87. The scale consists of 14 items and is rated on a 5-point Likert-type scale. The total score obtained from the sum of the items reflects the respondent's perceived level of stress, with higher scores indicating a higher level of perceived stress.

Stress levels were assessed by analyzing salivary cortisol concentrations.