Does optimism act as a buffer against posttraumatic stress over time? A longitudinal study of the protective role of optimism after the 2011 Oslo bombing.

Objective: Cross-sectional studies have revealed that high levels of optimism can protect against high levels of posttraumatic stress after exposure to trauma. However, this is the first study to explore (a) the protective role of optimism in a longitudinal perspective and (b) optimism’s protective effects on specific symptom clusters within the posttraumatic stress symptomatology. Method: This study used prospective survey data from ministerial employees (n = 256) collected approximately 1, 2, and 3 years after the 2011 Oslo bombing. To examine relationships between optimism and development of posttraumatic stress, we applied a series of latent growth curve analyses of both overall posttraumatic stress and the 5 clusters within the posttraumatic stress symptomatology (intrusions, avoidance, numbing, dysphoric arousal, and anxious arousal) with predictors and interaction terms. Results: The results showed that levels of exposure and optimism had main effects on starting levels of all clusters of posttraumatic stress. In addition, optimism had a protective-stabilizing effect on starting levels of avoidance, numbing, and dysphoric arousal. No associations between optimism and rate of change in symptoms clusters were found. Conclusion: These results suggest that optimism may help to neutralize the effects of high exposure on levels of symptoms of avoidance, numbing, and dysphoric arousal but not on the symptoms of intrusions and anxious arousal. Thus, individuals high in optimism still experience intrusions and anxious arousal after trauma, but may be better equipped to cope with these so they do not develop into avoidance, numbing and dyshorical arousal.