The impact of traumatic injury on mental health outcomes

Traumatic physical injury is a leading cause of physical and psychological disability, wielding a multi-faceted impact on an individual’s quality of life and a subsequent extensive global economic burden. Individuals who have experienced a traumatic injury have been shown to have elevated risk for depression, anxiety and PTSD. However, the trajectory pathways and predictors for these three outcomes within the traumatic injury population have yet to be delineated. An understanding of the risk factors and trajectory patterns for each outcome will enable greater specificity in screening for, and then clinical implementation of injury rehabilitation, both physically and psychologically. The program of research presented in this dissertation comprises three parts. First, a literature review of research investigating traumatic injury and mental health is outlined in Chapter One. The second section of the thesis comprises two subsequent chapters (Chapters Two and Three respectively) corresponding to empirical work investigating: Study 1: A comparison of the longitudinal trajectories of depression, anxiety and PTSD symptom severity following traumatic injury, including investigation of the mediating effects of age, gender and psychiatric history on these patterns. Study 2: The role that injury-related characteristics play in the development of depression, anxiety and PTSD symptomatology following injury, specifically the influence of injury site and severity as predictors of each mental health outcome. In a multi-site prospective longitudinal study, participants with a traumatic physical injury (N=1098) were assessed during hospital admission, and followed up at 3 months (N=932, 86%) and at 12 months (N=715, 71%). The same sample was used for both studies. Injury Site was measured using the Abbreviated Injury Scale 90 (AIS); and objective Injury Severity was measured using the Injury Severity Score (ISS). Participants completed the Hospital Anxiety and Depression Scale (HADS), Clinician Administered PTSD Scale (CAPS) and Mini International Neuropsychiatric Interview (MINI version 5.5). Random intercept mixed modelling analyses were conducted to evaluate the research aims. Study 1: Each mental health outcome exhibited a statistically significantly different trajectory from the others, despite PTSD and depression both demonstrating a recovery pattern. Anxiety was aligned with a delayed-onset trajectory. The inclusion of socio-demographic factors did not significantly influence these trajectories. Study 2: Injury severity was positively correlated with PTSD symptom severity, but not with anxiety or depressive symptoms. Head, face and external injuries were positively correlated with PTSD symptomatology. Lower extremity and external injuries were associated with depression. Finally, the presence of any injury, irrespective of site or severity, was associated with worse levels of each of depression, anxiety and PTSD symptomatology. The findings from this program of research suggest that traumatic injury has a negative impact on mental health within the initial 12-months following injury, which manifests in different trajectory patterns for depression, anxiety and PTSD symptom severity. Of particular clinical relevance is the delayed-onset pattern for anxiety, which exhibits a non-linear increase over 12 months without indicators of remission and therefore would benefit from early intervention. Additionally, recognition of factors that contribute to a poorer psychological adjustment, including sociodemographic factors and/or an injury located on an individual’s head, face, lower extremity or external injury may assist with screening and subsequent interventions aimed at mitigating not only the immediate psychological consequences; but also the overall social and economic burden that prolonged injury can cause.