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Epidemiology

Epidemiological research is concerned with the distribution and determinants of disease within a given population. At ACPMH, epidemiological research comprises two main arms, prevalence and vulnerability, which are discussed below.

Prevalence

This research program is focussed on increasing our understanding of the psychological impact of trauma, and how psychological recovery can be more effectively promoted. While the prevalence of posttraumatic stress disorder is often a focus of prevalence studies within trauma exposed populations, there is growing evidence that trauma leads to a wide range of psychiatric disorders.

National prevalence

Epidemiological studies in the US have indicated that traumatic events are commonly experienced in the general community, yet only a small percentage of those exposed will develop PTSD. Using data from the 1998 Australian National Survey of Mental Health and Well-being (NSMHWB), we estimated 12-month prevalence of PTSD to be 1•33%, a rate considerably lower than that found in comparable North American studies.

Among those who had experienced trauma, rape or sexual molestation were the traumatic events most likely to be associated with subsequent PTSD, with females at greater risk of experiencing these high risk traumas than males. For both sexes, PTSD was associated with high rates of anxiety, depression and substance use disorders. ACPMH is currently collaborating on a project looking to update this research using data from the most recent NSMHWB, conducted in 2007.

Prevalence of mental health disorders after injury

Traumatic injury affects millions of people each year, yet there is little understanding of the extent of psychiatric illness that develops after traumatic injury. In this prospective research, we utilised a large sample of participants who were assessed during hospital admission, and subsequently followed up at 3 months and 12 months after injury. At 12 month follow-up, 31% of patients reported a psychiatric disorder.
Twenty-two percent developed a psychiatric disorder that they had never experienced before, the most common of which were depression (9%), generalised anxiety disorder (9%), posttraumatic stress disorder (6%), and agoraphobia (6%). Given the prevalence and range of first-onset psychiatric disorder in this population, early identification and provision of appropriate treatment is important for optimal recovery following a traumatic injury.

Vulnerability

Research indicates that the majority of people are resilient following exposure to a traumatic event, and will experience a gradual reduction of anxious or depressed feelings. Yet some appear to have a higher vulnerability to posttraumatic psychopathology, and it is clear that for these people, such feelings can negatively impact overall recovery from trauma. This area of research aims to investigate what contributes to vulnerability for poor recovery following trauma exposure.

Screening for vulnerability

ACPMH has developed a screening instrument that identifies risk for developing posttraumatic stress disorder and depression after injury. The citation for the screen is:
O'Donnell, M. L., Creamer, M. C., et al. (2008). A predictive screening index for posttraumatic stress disorder and depression following traumatic injury. Journal of Consulting and Clinical Psychology 76(6): 923-932.
Click here to download a copy of the screen.

Impact of childhood trauma on vulnerability

A history of childhood trauma appears to increase vulnerability to PTSD after subsequent trauma, although it is unclear whether adult trauma survivors with and without a history of childhood trauma differ in their vulnerability to particular PTSD symptoms over time. This research involved two separate longitudinal studies using large samples of injury patients. First, we examined the extent to which childhood trauma is associated with more sustained psychiatric symptoms following subsequent trauma in adulthood, and to identify the factors that contribute to an increased risk of psychopathology after subsequent trauma. In a second study we mapped PTSD symptom response pathways to investigate whether differences could be found between groups of traumatic injury survivors with and without a history of childhood trauma. These findings deepen our understanding of why people with childhood trauma are more vulnerable to PTSD later in life.

Injury vulnerability study (IVS)

Until relatively recently, the psychiatric aspect of injury was largely ignored. The Injury Vulnerability Study aimed to address this gap and represents one of the largest studies of posttraumatic mental health ever undertaken. We collected data on a range of psychological, biological, and behavioural indices from over 1000 patients admitted to four Level 1 trauma services across Australia. Participants were then followed up at 3 months, and 1, 2 and 6 years after injury and administered a structured clinical interview assessing PTSD, mood, anxiety, and substance use disorders. The rich data collected as part of this project have allowed ACPMH researchers to conduct a detailed investigation into what makes people vulnerable to psychiatric disturbance following a serious injury. Findings of the IVS also led to the development of a world first screening tool to identify people who are at risk of developing PTSD or depression after injury.

Sleep and vulnerability

A history of insomnia has been found to increase vulnerability to mental health disorders such as anxiety and depression, but the extent to which this applies to posttraumatic disorders has not been investigated. Therefore, in this study we assessed sleep disturbance in the two weeks prior to traumatic injury and psychiatric disorder three months post-injury. The results showed that pre-trauma sleep disturbance increases the risk of developing a range of posttraumatic psychiatric disorders, including anxiety, affective, and substance use disorders. This effect persisted even after controlling for prior psychiatric disorders, which may account for the sleep disturbance. Assessing pre-trauma sleep disturbance in the early aftermath of trauma may therefore improve the ability of clinicians to identify a patient's risk for subsequent mental health problems.

The effects of mild traumatic brain injury (MTBI)

In recent years there has been an increased interest in the effects of MTBI, largely as a result of its prevalence among veterans returning from the conflicts in Iraq and Afghanistan. Our research has focussed on the relationship between MTBI and mental health after injury. For example, we found that MTBI represents a vulnerability to developing acute stress disorder (ASD) after injury. MTBI patients also report higher levels of distress associated with psychological symptoms. It appears that MTBI patients may represent a group at risk of poorer long term psychological adjustment. As such, ACPMH is conducting ongoing research into the interaction between MTBI and mental health, particularly the effect of MTBI on recovery from injury.

The impact of access to compensation on recovery outcomes

Previous research has found that access to compensation is associated with poor recovery outcomes following injury, however this relationship has rarely been examined outside of workers compensation populations. This research aimed to investigate the effect of access to other forms of compensation. We found that injury patients with access to motor vehicle accident (MVA) compensation have considerably poorer mental health and return-to-work outcomes than non-compensable patients. However this relationship was found to be highly complex. Further studies are required to examine the relationship between compensation and health in more detail.

Media and exposure to trauma/ Media and exposure to potentially traumatic work-related events

Journalists and other media personnel are often exposed to scenes involving injury, death, destruction, or grief, which can be stressful and impact wellbeing. In collaboration with ACPMH, The Dart Centre Asia Pacific conducted a six-month longitudinal study with a sample of media personnel. Participants met screening criteria for PTSD and depression at considerably higher rates than those reported in the general Australian population. Factors found to predict PTSD symptom severity at time of initial assessment, included history of psychological treatment, perception of life threat, distress during the most recent work-related trauma exposure, and dissatisfaction with support from family or friends. At follow-up assessment the predictors were: initial PTSD symptom severity, workplace social support variables, and the number of interim work-related trauma exposures. Given these findings, the media industry may have a role to play in mitigating the psychological impacts of work-related trauma exposure on staff.