The dangers of inflation: memories of trauma and post-traumatic stress disorder

Delayed post-traumatic stress and memory inflation of life-threatening events following a natural disaster: prospective study

BACKGROUND

The causes of delayed post-traumatic stress disorder (PTSD) are debated, and the validity of late-onset PTSD has been questioned.

AIMS

We aimed to examine predictors of delayed PTSD in a community sample of survivors of a natural disaster.

METHOD

Norwegian survivors of the 2004 Indian Ocean tsunami (n = 532) responded to a questionnaire at 6 and 24 months post-disaster. The questionnaire measured PTSD symptoms, recalled exposure and immediate stress responses to the disaster, recalled perceived life threat, personality dimensions, social support and other subsequent adverse life events.

RESULTS

When dichotomising PTSD symptom scores, 331 participants had low and 194 had high PTSD scores (early-onset PTSD) at 6 months. Of those with initially low scores, 43 (13.0%) had high symptom scores (delayed PTSD) at 24 months. The delayed PTSD group had a lower degree of initially assessed threat and witness experiences of death or suffering, lower immediate stress response and higher degree of memory inflation of perceived threat than the early-onset PTSD group. Among those with low PTSD scores at 6 months, onset of delayed PTSD was associated with neuroticism and memory inflation of life threat, but not with the degree of initially assessed disaster exposure or reports of subsequent adverse life events.

CONCLUSIONS

Lack of association between trauma exposure and delayed onset of PTSD symptoms casts doubt on whether the traumatic event is actually the primary causative factor for delayed PTSD. Our findings suggest that delayed PTSD may be a manifestation of personality factors and memory inflation of the severity of an event.

Fear but not fright: re-evaluating traumatic experience attenuates anxiety-like behaviors after fear conditioning

Fear allows organisms to cope with dangerous situations and remembering these situations has an adaptive role preserving individuals from injury and death. However, recalling traumatic memories can induce re-experiencing the trauma, thus resulting in a maladaptive fear. A failure to properly regulate fear responses has been associated with anxiety disorders, like Posttraumatic Stress Disorder (PTSD). Thus, re-establishing the capability to regulate fear has an important role for its adaptive and clinical relevance. Strategies aimed at erasing fear memories have been proposed, although there are limits about their efficiency in treating anxiety disorders. To re-establish fear regulation, here we propose a new approach, based on the re-evaluation of the aversive value of traumatic experience. Mice were submitted to a contextual-fear-conditioning paradigm in which a neutral context was paired with an intense electric footshock. Three weeks after acquisition, conditioned mice were treated with a less intense footshock (pain threshold). The effectiveness of this procedure in reducing fear expression was assessed in terms of behavioral outcomes related to PTSD (e.g., hyper-reactivity to a neutral tone, anxiety levels in a plus maze task, social avoidance, and learning deficits in a spatial water maze) and of amygdala activity by evaluating c-fos expression. Furthermore, a possible role of lateral orbitofrontal cortex (lOFC) in mediating the behavioral effects induced by the re-evaluation procedure was investigated. We observed that this treatment: (i) significantly mitigates the abnormal behavioral outcomes induced by trauma; (ii) persistently attenuates fear expression without erasing contextual memory; (iii) prevents fear reinstatement; (iv) reduces amygdala activity; and (v) requires an intact lOFC to be effective. These results suggest that an effective strategy to treat pathological anxiety should address cognitive re-evaluation of the traumatic experience mediated by lOFC.

Stress and development of depression and heavy drinking in adulthood: moderating effects of childhood trauma

PURPOSE

Studies suggest that childhood trauma is linked to both depression and heavy drinking in adulthood, and may create a lifelong vulnerability to stress. Few studies have explored the effects of stress sensitization on the development of depression or heavy drinking among those who have experienced traumatic childhood events. This study aimed to determine the effect of childhood trauma on the odds of experiencing depression or heavy drinking in the face of an adult life stressor, using a large population-based Canadian cohort.

METHODS

A total of 3,930 participants were included from the National Population Health Survey. The associations among childhood trauma, recent stress and depression/heavy drinking from 1994/1995 to 2008/2009 were explored using logistic regression, as were interactions between childhood trauma and recent stress. A generalized linear mixed model was used to determine the effects of childhood trauma and stressful events on depression/heavy drinking. Analyses were stratified by sex.

RESULTS

Childhood trauma significantly increased the odds of becoming depressed (following 1 event: OR = 1.66; 95%CI 1.01, 2.71; 2+ events, OR = 3.89; 95%CI 2.44, 6.22) and drinking heavily (2+ events: OR = 1.79; 95%CI 1.03, 3.13). Recent stressful events were associated with depression, but not heavy drinking. While most interaction terms were not significant, in 2004/2005 the association between recent stress and depression was stronger in those who reported childhood trauma compared to those with no childhood trauma.

CONCLUSIONS

Childhood trauma increases risk for both depression and heavy drinking. Trauma may moderate the effect of stress on depression; the relationship among trauma, stress and heavy drinking is less clear.

The injured mind in the UK Armed Forces

The mental health of the UK Armed Forces is a topic much debated by healthcare professionals, politicians and the media. While the current operations in Afghanistan, and the recent conflict in Iraq, are relevant to this debate, much of what is known about the effects of war upon the psyche still derives from the two World Wars. This paper will examine the historical and contemporary evidence about why it is that some Service personnel suffer psychological injuries during their military service and others do not. The paper will also consider some of the strategies that today's Armed Forces have put in place to mitigate the effects of sending military personnel into danger.