Description

Rape is a common cause of post-traumatic stress disorder (PTSD) among women, as around 30-50% will develop PTSD in the aftermath of rape, leading to severe mental and physical suffering. There is a lack of evidence-based knowledge how to prevent the development of PTSD after rape. Women may suffer from PTSD for years before receiving therapy.

Prolonged Exposure Therapy (PE) is well documented as a therapy. However, preventing the development of PTSD have the potential to spare women of the suffering, prevent both mental and somatic health problems, and also reduce health care costs. Currently a brief protocol based on PE, has been developed, modified prolonged exposure (mPE), consisting of three to five once or twice weekly 60 minutes sessions, and studies indicate that if implemented early after rape, mPE may prevent the development of PTSD.

Specialized services for victims, Sexual Assault Care (SAC) centers have been established in Norway, offering forensic documentation, medical treatment and psychosocial follow-up. The follow-up service varies widely and no evidence-based preventive measures have been implemented.

The investigators propose to conduct a multi-site (SAC centers in Trondheim, Oslo, and Sandefjord) randomized control trial (RCT) in which patients are recruited early after a rape, and randomized within 2 weeks to intervention (mPE) or treatment as usual (TAU).

The patients will be stratified by treatment center and randomized in permuted blocks of varying sizes according to a computer-generated randomization key prepared by the Clinical Research Unit at .

Around 800 patients will attend one of the four SACs per year. Based on experience from others the investigators anticipate that approximately 200 patients will be eligible and consenting to participation in this study and that around 50% of participants will dropout during the study period. A final sample size of 100 completed participants (50 in the intervention and 50 in TAU) will achieve 80% power to detect a standardized mean difference (SMD) of 0.44 for each of the primary outcomes in a design with 3 repeated measurements assuming an autoregressive, AR(1), covariance structure when the standard deviation is 1, the correlation between observations on the same subject is 0.5, and the alpha level is 0.05 (PASS Sample Size software - Tests for Two Means in Repeated Measures Design). Given the rather conservative estimate for inclusion, the investigators will need 1.5-2 years to recruit sufficient numbers.

Given the nested structure of the data - e.g., multiple measurement points nested within patients, patients nested within therapists, therapists nested within study sites - data will be analyzed by multilevel modeling. In addition, multilevel modeling is a robust method to deal with the missing data given the expected high percentage of drop-out from the study. The primary analysis will be an intention-to-treat analysis.

Predictors and moderators of the intervention, like stress response (measured by level of cortisol in hair and saliva) and sleep patterns (measured with actigraphy), will be explored.

The planned intervention is a brief and simple program, with large potential to be implemented as routines if proven effective, and thus inform clinical guidelines.