Fawzi and colleagues (1997) studied whether the usual way of thinking about posttraumatic stress disorder (PTSD), as described in the fourth edition of the standard Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), applies to Vietnamese refugees in the United States. As part of their study, 74 refugees were interviewed (in their native language) regarding various PTSD symptoms and the traumatic events they had experienced, such as torture. As expected, the number of PTSD symptoms correlated with the number of traumatic events. In a further analysis of the pattern of symptoms (which symptoms go together with which), they conducted a factor analysis that resulted in four factors.
In correspondence with the DSM-IV, the first three factors represented dimensions of arousal, avoidance, and reexperiencing, respectively (see Table [15-10]). However, in contrast to the DSM-IV defined subcategories where avoidance represents one dimension of symptomatology, avoidance appeared to be separated into two factors in this sample. The second factor reflected avoidance associated with general withdrawal or numbing of responsiveness, with high factor loadings for "unable to feel emotions" and "less interest in daily activities." The fourth factor reflected avoidance of stimuli related to the traumatic event(s).
Explain these results to a person who is familiar with correlation but is unfamiliar with factor analysis.
Table 15-10
Factor Loading for Principal Components Analysis (Factor Analysis) of PTSD-IV Symptoms for 74 Vietnamese Refugees

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Symptom Dimension Factor Loading Recurrent nightmares Difficulty concentrating Feeling irritable/outburst of anger Inability to remember parts of the most traumatic events Trouble sleeping Avoiding activities that remind you of traumatic events Feeling jumpy, easily startled % Variance explained 44% Avoidance/withdrawal Unable to feel emotions Less interest in daily activities Feeling detached or withdrawn Feeling jumpy, easily startied Feeling as if you don't have a future .51 % Variance explained 24% Recurrent thoughts/memories of most terrifying events Feeling as though the event is happening again Sudden emotional or physical reaction when reminded of most traumatic events % Variance explained Avoidance of stimuli related to trauma event s) Avoiding thoughts or feeling associated with traumatic events % variance explained 11%