Latest Evidence on PTSD May Bring Changes in DSM-V: Subthreshold events can lead to disorder.
by DAMIAN MCNAMARA
Clinical Psychiatry News
Volume 35, Issue 11 (November 2007)
MIAMI BEACH – The definition of posttraumatic stress disorder should change with the next revision of the Diagnostic and Statistical Manual of Mental Disorders, Dr. Michael First said at the annual meeting of the American Academy of Psychiatry and the Law.
Such a change is supported by recent evidence suggesting that people can develop PTSD even in the absence of a high-magnitude traumatic event.
“Does presence of a PTSD syndrome automatically imply exposure to severe trauma? That is true only if PTSD can arise as a specific response to severe trauma,” he said. “However, if there are cases where PTSD develops in absence of severe trauma, it is not a valid assumption,” added Dr. First, professor of clinical psychiatry at Columbia University, New York.
The science since the last major revision–the DSM-IV Text Revision in 1992–suggests exposure to traumatic stress might not be required in all cases of PTSD, he said.
Initially, case reports suggested PTSD could arise following subthreshold events such as divorce, bereavement, or the end of a romantic relationship. More recent scientific studies have supported the findings. For example, PTSD was equally present in traumatized, equivocally traumatized, and nontraumatized participants in a study by researchers at McLean Hospital, Belmont, Mass. (J. Anxiety Disord. 2007;21:176-82). They assessed 103 adults enrolled in a depression study instead of using a traditional design that would assess only people who had experienced a trauma for subsequent PTSD.
“Investigators on this study decided to look at PTSD whether there was trauma or not,” said Dr. First, who is also a research psychiatrist at the New York State Psychiatric Institute. There were 198 traumatic events of any severity. A total of 54 participants rated the trauma as an A1 event (meeting DSM-IV-TR A1 criteria), 13 reported equivocal trauma, and 36 reported never having experienced trauma. Without regard to trauma history, 81 participants met criteria for PTSD, which was equally prevalent (around 80%) in each of the three groups, he said. “This study raises major questions about major trauma being required to cause PTSD,” Dr. First said.
In another study, researchers surveyed a large cohort in the Netherlands that had experienced a traumatic or life-altering event (Br. J. Psych. 2005;186:494-9). A total of 299 individuals reported a lifetime traumatic event, such as an accident or abuse, compared with 533 who reported life events such as relationship problems or the sudden death of loved one. “The scores for traumatic and nontraumatic life events were about the same for PTSD, the exception being those individuals whose trauma was physical or sexual abuse,” Dr. First said. “So this is another study supporting [the idea] that it does not have to be a severe, A1-level trauma to qualify for PTSD.”
In addition, evidence from behavioral genetics studies suggests that PTSD, like other anxiety and mood disorders, arises from a combination of non-disorder-specific genetic and environmental factors, he noted. “The litigation about PTSD when we were working on DSM-IV was going crazy, so we thought it would be wise to limit it to high-magnitude events,” Dr. First said.
So what can be done regarding the PTSD entry in the upcoming DSM-V? “It would be really nice if PTSD was specific to severe trauma. “There is a lot of hope for PTSD,” he said, “but a lot of work needs to be done to get it back to where it should be–related to extreme stress.”
Before publication of the DSM-IV, “there was a huge debate over how broad versus how narrow criterion A should be.” One of the problems is that the some of the criteria, such as irritability, insomnia, and a marked disinterest in activities, also occur in depression. Even items that do not overlap with other disorders might not be pathologic for PTSD. A possible solution is to evaluate criteria B, C, and D for diagnostic specificity to differentiate PTSD from other mood and anxiety disorders. Then only symptoms related to exposure to extreme stress would be retained, Dr. First added.
A different entry for PTSD in the DSM-V is all but certain if history is any indication. Since the first publication of the DSM, the entry has changed with each update. In the DSM-I, the precursor to PTSD was called “traumatic neurosis.” In DSM-II, it became “transient situational disturbances.” This vague definition became more specific in the DSM-III, which introduced PTSD-qualifying stressors–a recognizable stressor that would evoke significant symptoms of distress in almost everyone, distress that is generally outside the usual human experience. The DSM-III-R updated this to refer to an event outside of normal human experience. “The manual gave examples for the first time, suggesting only severe stressors lead to PTSD,” Dr. First said. The sudden destruction of one's home or community was an example.
PTSD stands out as one of those few disorders in the DSM with an etiology that is included in the definition with a specificity regarding trigger events. “This idea of specificity hung around with the DSM, even though the definition changed,” he said.
Prior to publication of DSM-IV, a field trial of the PTSD criteria was conducted, part of which determined the prevalence and magnitude of stressful events. Among 400 treatment-seeking outpatients and 128 community participants, for example, investigators found a huge prevalence of high-magnitude events: 84% of treatment seekers and 93% of community participants had at least one lifetime, high-magnitude event. “It's part of human experience at some point to be exposed to traumatic stress, so the requirement that it be outside the range of normal human experience was eliminated from the DSM-IV,” Dr. First said. Only 66 people, 13% of cases, reported that they had experienced a past-year low-magnitude event, “so the conclusion was that PTSD occurs very rarely in absence of high-magnitude events,” he said.
Now the matter is up for debate prior to release of DSM-V.