Posttraumatic growth, depression and posttraumatic stress in relation to quality of life in tsunami survivors: a longitudinal study

BACKGROUND Quality of life (QoL) may often be reduced in survivors of a natural disaster. This paper investigated how posttraumatic growth (PTG), depression and posttraumatic stress interact and independently predict QoL in a longitudinal study of disaster survivors. METHODS A total of 58 Norwegian adults who were present in Khao Lak, Thailand at the time of the 2004 Southeast Asia Tsunami completed self-report questionnaires 2 and 6 years after the disaster. The participants reported symptoms of depression and posttraumatic stress as well as PTG and QoL. Multiple mixed effects regression analyses were used to determine the independent effects of PTG, depression and posttraumatic stress on QoL measured 2 and 6 years after the disaster. RESULTS Posttraumatic stress and depression were negatively related to QoL. PTG was not significantly related to QoL in a bivariate analysis. However, considerable interaction effects were found. Six years after the tsunami, high levels of posttraumatic stress were related to lower QoL in those participants with low levels of PTG, whereas lower levels of depression were related to higher QoL in those participants with high levels of PTG. CONCLUSIONS Posttraumatic stress and depression are negatively associated with QoL after a natural disaster. PTG may serve as a moderating factor in this relationship.