Posttraumatic Stress Disorder 517
Hypothesis 1
In PTSD encoding of trauma information is characterized by a data- driven processing mode
that results in enhanced processing of threat and danger features of the trauma.
Studies employing semistructured interviews or questionnaires have investigated
whether individuals with PTSD differed from those without PTSD in how they pro-
cessed the trauma. In a study of 92 individuals who were assaulted, those with PTSD
reported significantly more mental defeat, mental confusion, and detachment during
the assault than those without PTSD (Dunmore et al., 1999). In a prospective study
these same cognitive variables predicted PTSD symptom severity at 6- and 9-month
follow-up (Dunmore et al., 2001). In another study individuals with PTSD following an
assault reported more trauma memory dissociation, data- driven processing, and lack of
self- referent processing than those without PTSD, and these variables predicted PTSD
symptoms at 6-month follow-up (Halligan et al., 2003). However, these cognitive pro-
cessing variables and the memory disorganization associated with trauma encoding may
not be specific to PTSD when compared to other emotional sequela of trauma such as
depression and phobias (Ehring, Ehlers, & Glucksman, 2006).
Item-cued directed forgetting is an information- processing paradigm that can be
used to investigate the differential encoding of trauma information. Individuals are
instructed to either remember or to forget a series of words, with subsequent recall
usually worse for “to-be- forgotten” words than “to-be- remembered” items. In a study
of adult survivors of childhood sexual abuse, those with PTSD showed no recall defi-
cits or enhanced processing of trauma words, indicating that they did not exhibit an
avoidant encoding style for trauma words (McNally, Metzger, Lasko, Clancy, & Pit-
man, 1998; see also Zoellner, Sacks, & Foa, 2003, for similar findings). In an analogue
study in which students watched real-life footage of a hospital emergency room case,
those instructed to focus on medical procedures reported significantly fewer intrusive
recollections of the film in the subsequent week although there was no difference in
self- reported memory disorganization (Laposa & Alden, 2006). A focus on medical
procedures is consistent with reliance on a more organized, contextual processing of
stressful situations. Overall there is consistent support for Hypothesis 1, that individuals
with PTSD evidence a problematic encoding of trauma information, when specialized
self- report measures are employed. Experimental support for this hypothesis has been
less consistent and clearly requires further research.
Clinician Guideline 12.14
Individuals with PTSD encode traumatic information in a manner that results in a disor-
ganized, fragmented memory of the trauma. However, the exact nature of the problematic
encoding style remains uncertain, although perceptual or data- driven processing may pre-
dominate over conceptually based processing. For the cognitive therapist, assessment of the
trauma memory should include processing variables like mental defeat, lack of self- referent
perspective, extent of data- driven versus conceptual-based processing, mental confusion,
and detachment.