This study was done to examine how laughter therapy impacts serotonin levels, QOL and depression in middle-aged women and to perform a path analysis for verification of the effects.

A quasi-experimental study employing a nonequivalent control group and pre-post design was conducted. Participants were 64 middle-aged women (control=14 and experimental=50 in 3 groups according to level of depression). The intervention was conducted five times a week for a period of 2 weeks and the data analysis was conducted using repeated measures ANOVA, ANCOVA and LISREL.

Results showed that pre serotonin and QOL in women with severe depression were the lowest. Serotonin in the experimental groups increased after the 10th intervention (p=.006) and the rise was the highest in the group with severe depression (p=.001). Depression in all groups decreased after the 5th intervention (p=.022) and the biggest decline was observed in group with severe depression (p=.007). QOL of the moderate and severe groups increased after the 10th intervention (p=.049), and the increase rate was highest in group with severe depression (p<.006). Path analysis revealed that laughter therapy did not directly affect depression, but its effect was indirectly meditated through serotonin variation (p<.001).

Results indicate that serotonin activation through laughter therapy can help middle-aged women by lessening depression and providing important grounds for depression control.