Background. Natural disasters such as earthquakes affect large numbers of people. Given the extent of the mental health problem following earthquakes, brief, effective and cost-effective treatment interventions are urgently needed. The present study examined whether cognitive-behavioural treatment could be shortened to a minimum number of sessions without undermining its effectiveness in post-traumatic stress disorder (PTSD).

Method. The study participants (N=231) were consecutive referrals to five project sites in the earthquake region in Turkey a mean of 13 months after the disaster. A modified behavioural treatment (BT) was used, which involved self-exposure instructions based on an enhancement of ‘sense of control’ rather than a habituation rationale and minimal cognitive interventions. The duration of treatment was variable, involving as many sessions as required for clinical improvement. Survival analysis was used to explore the minimum number of sessions required for clinical improvement, and multiple regression analysis to examine the predictors of outcome.

Results. The survivors received a mean of 4·3 sessions. Significant treatment effects and clinically meaningful effect sizes were noted on all measures. The treatment improved all PTSD and depression symptoms. The cumulative proportion of improved cases was 76% after one session and 88% after two sessions. No baseline variable predicted treatment outcome.

Conclusions. The modified BT appears to be promising as an effective one- or two-session intervention for earthquake survivors. It may be particularly useful in large-scale disasters as a cost-effective treatment that can be relatively easily disseminated to mass populations. Further research is needed to clarify the possible role of a treatment focus on sense of control in rapid recovery from traumatic stress.