A generalized external control expectancy in Vietnam veterans with post traumatic stress disorder: A new hypothesis

Bruce Altman (1988)

Data from the Veterans Administration Medical Center (Pitman et al, 1987) were investigated in order to ascertain the relationship between post traumatic stress disorder (PTSD) and locus of control (Rotter 1966). The Structured Clinical Interview for DSM-III (SCID) version NPV was administered by a board certified psychiatrist for the purpose of assigning subjects to the PTSD or control group. The Minnesota Multiphasic Personality Inventory (MMPI) and The Rotter I-E scale, were used to provide measures of the independent variables, personality factors and locus of control, while the Mississippi Scale for Combat-Related PTSD was used to assess the severity of PTSD, the dependent variable. When education was controlled for, a significant difference was found between the PTSD group and the control group, on locus of control. This finding suggests that Vietnam veterans with PTSD had a more external locus of control than an equivalent group of Vietnam veterans without PTSD. In addition, I-E was found to be related to the Psychasthenia (PT) and Psychopathic Deviate (PD) variables on the MMPI as well as to PTSD severity. These results are interpreted in the context of a "generalized external control hypothesis" in which veterans with an external locus of control are thought to have a very strong generalized attitude about their inability to exert any control over outcomes and events in their lives, particularly political outcomes and events, which in turn predisposes the veteran to feelings of helplessness.