The diagnostic criteria for PTSD, stipulated in the Diagnostic and Statistical Manual
of Mental Disorders IV (Text Revision) (DSM-IV-TR), may be summarized as:
Exposure to a traumatic event
This must have involved both (a) loss of "physical integrity", or risk of serious
injury or death, to self or others, and (b) an intense negative emotional response.
(The DSM-IV-TR criterion differs substantially from the previous DSM-III-R stressor
criterion, which specified the traumatic event should be of a type that would cause
"significant symptoms of distress in almost anyone," and that the event was "outside
the range of usual human experience.")
One or more of these must be present in the victim: flashback memories, recurring
distressing dreams, subjective re-experiencing of the traumatic event(s), or intense
negative psychological or physiological response to any objective or subjective
reminder of the traumatic event(s).
Persistent avoidance and emotional numbing
This involves a sufficient level of:
⇒ reduce their substance use or gambling
⇒ avoidance of stimuli associated with the trauma, such as
certain thoughts or feelings, or talking about the event(s);
⇒ avoidance of behaviors, places, or people that might lead
to distressing memories;
⇒ inability to recall major parts of the trauma(s), or decreased
involvement in significant life activities
⇒ decreased capacity (down to complete inability) to feel
⇒ an expectation that one's future will be somehow constrained
in ways not normal to other people.
Persistent symptoms of increased arousal not present before
These are all physiological response issues, such as difficulty falling or staying
asleep, or problems with anger, concentration, or hypervigilance.
Duration of symptoms for more than 1 month
If all other criteria are present, but 30 days have not elapsed, the individual
is diagnosed with Acute stress disorder.
The symptoms reported must lead to "clinically significant distress or impairment"
of major domains of life activity, such as social relations, occupational activities,
or other "important areas of functioning".
Since the introduction of DSM-IV, the number of possible events which might be used
to diagnose PTSD has increased; one study suggests that the increase is around 50%.
Various scales exist to measure the severity and frequency of PTSD symptoms