The counterintuitive effect of a disaster: The need for a long-term perspective

Beaglehole and colleagues’ (2015) finding of decreased rates of both psychiatric bed occupancy and admission rates in the 18-month period following the Christchurch earthquakes is intriguing but not unexpected. Similar observations were made during the 1940 London Blitz when extensive arrangements were made for an epidemic of psychiatric casualties needing inpatient care that did not eventuate (Jones et al., 2004). What do these findings suggest about our understanding of the impact of traumatic events?

First, it is imperative not to conclude that exposure to disasters has little impact on mental health. To the contrary, the longitudinal Christchurch Health and Development Study reported increased rates of post-traumatic stress disorder (PTSD), depression and anxiety disorders (1.4X) in those exposed to the same Christchurch earthquakes compared to an unexposed group (Fergusson et al., 2014). In this cohort, 10.8–13.3% of the overall rate of mental disorders at age 35 years was attributed to the earthquakes. These disorders are generally treated in outpatient settings and hence not reflected in admission rates. Also, those affected survivors with no prior contact with treatment services have the greatest degree of unmet need (Brewin et al., 2008) and are therefore less likely to be reflected in changes in service utilization.

In this context, it is possible that the lower rates of hospital admissions may be attributed to the disruption of the physical and social milieu that can occur in the aftermath of disasters. This can indirectly influence the help seeking and behaviour of those suffering from pre-existing psychiatric disorders. A study conducted following the1983 Ash Wednesday bushfires established a register of cases presenting for care and found that some patients with anxiety and depression disorders functioned better than in previous episodes of illness (McFarlane, 1986). The practical demands of the post disaster environment distracted the sufferers from their internal preoccupations. In essence, people seemed to function better when in survival mode. This effect may also account for the drop in the number of psychiatric admissions in the Christchurch area reported by Beaglehole et al. (2015).

The Ash Wednesday study also noted that although a minority of cases did present for treatment in the first 12 months post disaster, a significant number of cases sought care more than 2 years after the event (McFarlane, 1986). Hence, the timeframe of 18 months reported in this study may predate the maximal impact of the disaster on psychiatric disorders requiring treatment.

The lower rates of hospital admissions may also reflect an intervention effect because of the mental health resources invested in the community after the disaster, as Beaglehole et al. (2015) suggested. One paradoxical effect is that these services may not improve access to care, as Brewin et al. (2008) noted after the 2005 London terrorist bombings. A large number of individuals with a psychiatric disorder who sought help with a general practitioner following the bombings were told that their reactions were normal and hence did not warrant intervention, contrary to their needs as identified in this outreach treatment study. Paradoxically, the traumatic setting of these individuals’ symptoms was a barrier for referral to care. Hence there is a complex set of dynamics in a health care system following a disaster that may impact hospital admission rates in the first 18 months of the recovery phase and, consequently, these rates may not accurately reflect the acute morbidity or long-term impact.

A further question is whether there were lower rates of home ownership by people who have had previous psychiatric admissions and this allowed them to move away from the earthquake-affected region. Hence they may be over-represented in those who left Christchurch.

The final issue is a historical one, and relates to the persistent tendency to focus on the acute effects of these events at the expense of the long-term consequences. The influence of models derived from military psychiatry on the management of acute battle casualties and the need to maintain a fighting force is pervasive. This perspective began to change in the aftermath of the Vietnam War when it was recognized that low rates of acute combat stress reactions led to the incorrect prediction of little long-term morbidity; however, we still have a long way to go. This narrow focus on the acute setting is still observed in civilian settings following disasters, where there continues to be an overemphasis on the provision of acute interventions, such as counselling or debriefing, despite the lack of evidence for their effectiveness (Brewin et al., 2008). An important question arising from the Beaglehole et al. (2015) study is what will the disorder and help-seeking trends be like in future years following this disaster? Beaglehole et al. provide evidence that acute disability is less common than most clinicians anticipate following the Christchurch earthquakes. This experience may lead to a failure to predict and manage the long-term morbidity of disasters.