These original data for this research were documented in the clinical diary records of an army psychiatrist on deployment in Vietnam during 1969–70. This study is unique due to the original battlefield diagnosis data used for foundation comparison analysis and longitudinal retrospective case control paired measurement. In battlefield psychiatric assessment diagnostic data recorded in Vietnam during 1969–70 of 119 Australian military servicemen (Experimental group) who presented battlefield trauma exposure reactions were examined. The research case controls (Control group) are 275 Australian Vietnam veterans selected from data at the Australian War Memorial Research Centre. Case control identified participants did not present with medical symptoms in 1969-70 and presented the same demographic profile as the Experimental group population. This research examined whether initial psychiatric illnesses initiated by battlefield trauma exposure in 1969-70 by a cohort of Vietnam veterans would have long term pernicious effects on their physical and psychological health, relationships and employment status. This research compared, PTSD, delayed onset PTSD, severity of combat exposure and depressive symptoms, quality of dyads, general health and quality of life. The analysis of specific demographic variables determined the means, standard deviations, and medians for those continuous variables for both groups from 1969-70 (n=394) and 2006-07 (n=97). The 2006-07 Experimental group (n=21) represents 17.65% and the Control group (n=76) represents 28.15% of the original groups selected and matched from 1969-70 data. These participants completed a battery of psychometric questionnaires and a follow up telephone interview. Demographic variables were evaluated for inclusion as covariates. These demographic variables were correlated with combat exposure and the presentation of PTSD in 1969-70 and 2006-07. PTSD identified in 2006-07 was modelled as a latent variable with three manifest indicators (re-experiencing, hyper-arousal and avoidance). Categorical variables were determined by frequency tables for respective group participants. Group differences in continuous variables were analysed by t-test or the Wilcoxon signed rank sum test accounting for non-normal distributions. Categorical variables, chi-square tests or Fisher's Exact Tests were performed when assumptions of chi-square tests were violated. Research participants from 1969-70 and 2006-07 did not indicate a significant difference in demographic, categorical or continuous variables. Initial 1969-70 battlefield psychiatric diagnosis TSD did indicate of a causal link to delayed onset PTSD in research participants in 2006-07. The PTSD (2006-07 diagnosis) indicated a descriptive difference, 64 of the 76 Control met the diagnostic criteria, while 19 of the 21 Experimental met the criteria. A significant difference was identified in the 2006-07 presence and severity of depression, two symptoms (intrusion and avoidance) of PTSD and the reported combat exposure. The prevalence of delayed onset PTSD was also highlighted. Obtaining original battlefield psychiatric diagnoses is rare. Comparison with an identifiable Control group after 35 years informs knowledge of how military personnel cope with battlefield exposure. Specifically concluding that; battlefield exposures during 1969-70 for the majority of the research participants have impacted detrimentally on their psychological and physical health, relationships, employment and ongoing overall wellbeing to this day. Delayed onset PTSD is the principal indicator of this current state for these veterans. / Thesis (Ph.D.) - University of Adelaide, School of Population Health and Clinical Practice, 2008