Katherine K. Dahlsgaard, lead psychologist of the Anxiety Behaviors Clinic at Children's Hospital of Philadelphia, wrote this for the "Healthy Kids" blog.

Teenage girls are sexually assaulted with alarming frequency and many will go on to develop post traumatic stress disorder (PTSD). If left untreated, PTSD can make life hell for the sufferer for years after the original trauma, and increase the likelihood of other problems; most common are anxiety, depression, substance abuse, and self-destructive behaviors.

But what treatment is appropriate and effective for PTSD in girls who have been sexually abused? An important study, recently done here in Philadelphia, points to a type of cognitive-behavioral therapy called prolonged exposure.

Typically, sufferers of PTSD go to great - and understandable - effort to avoid memories or reminders of the traumatic event. Even if the individual with PTSD attends therapy for relief, they will often avoid bringing up the trauma. Many well-meaning therapists, fearful of increasing their patients' distress, will allow the avoidance.

The problem is that avoidance doesn't work and tends to worsen the symptoms of intrusive memories, flashbacks and emotional numbing. In prolonged exposure, therapists encourage PTSD sufferers to stop avoiding and instead tell the story of their trauma over several sessions. By repeatedly recounting the details, sufferers can process their fear and learn firsthand that memories, while extremely upsetting, are not unsafe. PTSD symptoms decrease as a result.

There is much evidence that prolonged exposure is a highly effective therapy for adults with PTSD, but had not been researched with adolescents. Edna Foa and colleagues from the Center for the Treatment and Study of Anxiety at the University of Pennsylvania addressed this by completing a study with 61 girls ages 13 to 18 who had been sexually abused and were seeking treatment at Philadelphia's Women Organized Against Rape. The teens, after consenting to the study, were randomly assigned to get prolonged exposure therapy or traditional supportive counseling by WOAR therapists.

Results showed that the girls who received prolonged exposure did a lot better than those who got supportive counseling: They were much less likely to have PTSD - and depression - at the end of the study and at a follow-up one year later. Of note: none of the girls assigned to supportive counseling chose to describe their trauma during treatment.

The results are particularly important, says Foa, the study's lead author, because the therapists were counselors in a clinic that serves sexually abused survivors. Prolonged exposure in the hands of these counselors significantly reduced PTSD, depression, and dysfunctional symptoms more than supportive counseling despite the fact that the therapists, while proficient in delivering supportive counseling, were not familiar with prolonged exposure until they received a five-day workshop at the beginning of the study.

And on that, I will end this post with a special shout-out to all the counselors at WOAR who provided their services for the study and are daily on the front lines of treatment for sexual assault survivors. You are hometown heroes.