Date of Award


Document Type


Degree Name

Doctor of Psychology (PsyD)


Graduate Department of Clinical Psychology


Contemporary psychiatric nosology defines dissociation as "a disturbance or alteration in the normally integrative functions of identity, memory, or consciousness" (Ruiz, Poythress, Lilienfeld, & Douglas, 2008; p. 511). Dissociation as a reaction to a traumatic event remains a controversial issue. This study explored for differences in the extent and forms of dissociation, intrusion, and avoidance in human-made trauma and natural disaster trauma. A total of 232 participants were drawn from 6 samples. Natural trauma was experienced by 2 groups in Haiti (earthquake), and one in Japan (tsunami). Human trauma was experienced by samples in India (abandonment, rejection/ostracism), Southern Sudan (civil warfare), and the West Bank (war and terrorism). In order to measure the traumas experienced and the magnitude and forms of dissociation in these populations, participants were given the Cumulative Trauma Scale (CTS) which measures the type of trauma as well as the duration of the trauma experienced; the Impact of Events Scale- Revised version (IES-R) which measures intrusion, avoidance factors, and hyperarousal in response to a traumatic event; and the Dissociative Experiences Scale (DES) which is a self-report measure distinguishing normal dissociation from pathological dissociation. The statistics that were used for this study included internal consistencies for the scales, descriptive statistics for each measure (means, SD), correlations among demographic measures and scales, and comparisons among the 6 samples. Results indicated clear differences in the trauma experienced by participants who were exposed to natural and human-induced trauma. However, the impact of trauma in these groups seemed little related to whether the trauma was from natural or human causes. No significant effect was found on the IES-R total score; however, IES-R items 4, 6, 8, 10, and 21 showed significant differences between groups. Total trauma as reported on the DES-T did not differ between natural and human induced trauma, but item scores suggested a somewhat different pattern of dissociation symptoms. Cultural differences and differences in resources, support systems, and in reporting distress may have more influence on the distress that participants reported than whether the trauma was due to human or natural causes. Other uncontrolled factors that may affect results include age, gender, socio-economic status, and education. These data raise the question of whether it will be necessary to make comparisons within a common cultural setting to further identify distinct symptomatic patterns related to whether traumas are human or nature-induced. It is also possible that the measures employed are not sensitive to differential effects of human and nature-induced trauma.

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