The conventional two-class psychiatric conceptualization of PTSD has been criticized for ignoring the existence of “trauma without symptoms” and “symptoms without trauma”.

To present and test a new four-class conceptualization of the relationship between trauma and symptoms that responds to the above criticism. The proposed four classes are: PTSD (high trauma and high symptoms); Resilient (high trauma but low symptoms); Stress Prone (low trauma but high symptoms); and Ideal Norm (low trauma and low symptoms).

To demonstrate fit between new conceptualization and empirical data.

Sample: 673 adults age 18-19. Measures: a trauma index incorporating five types of frequently experienced potentially traumatic events; a standardized 16 item measure of posttraumatic stress symptoms; multi-item scales of two protective factors (social support and self efficacy). Statistical procedures: cluster analysis and ANOVA.

Statistical cluster analysis produced four classes of individuals: 19% of sample had high trauma and high symptoms (PTSD); 23% had high trauma and low symptoms (Resilient); 21% had low trauma and high symptoms (Stress Prone); and 36% had low trauma and low symptoms (Ideal Norm). “Resilient” and “Norm” groups also had high “protection”. Four-class model was a better fit to data than two-class model.

The proposed re-conceptualization, using four classes and incorporating protective factors, better describes the empirical trauma-symptom relationship than the conventional two-class psychiatric conceptualization of PTSD; and begins to clarify the psycho-social dynamics of the trauma-psychopathology relationship.