Examples are reported of PTSD cases showing full symptomatology (intru
sive imagery, avoidance behaviour, disordered arousal) in the absence
of a single, acute, dramatic trauma of the kind required by the curren
t DSM-III-R definition. Such trauma is thus not a necessary condition
for PTSD, and other evidence shows it to be not a sufficient condition
. It is suggested that the DSM-III-R Axis IV distinction between acute
and enduring psychosocial stressors be incorporated into the definiti
on to distinguish two pathways to stress disorder, post-traumatic (PTS
D) and prolonged duress (PDSD). Differential treatment implications of
the two routes are noted.