In contrast to its effectiveness for irrational fears such as spiders, CBT has not done so well for traumatized individuals, particularly those with histories of childhood abuse. Only about one in there participants with PTSD who finish research studies show some improvement. Those who complete CBT treatment usually have fewer PTSD symptoms, but they rarely recover completely: Most continue to have substantial problems with their health, work, or mental well-being.
In the largest published study of CBT for PTSD more than one-third of the patients dropped out; the rest had a significant number of adverse reactions. Most of the women in the study still suffered from full-blown PTSD after three months in the study, and only 15 percent no longer had major PTSD symptoms. A thorough analysis of all the scientific studies of CBT show that it works about as well as being in a supportive therapy relationship.
Bessel van der Kolk – The Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma p.221