Preclinical perspectives on posttraumatic stress disorder criteria in DSM-5

Modelling posttraumatic stress disorders in animals

Animal models of posttraumatic stress disorder are useful tools to reveal the neurobiological basis of the vulnerability to traumatic events, and to develop new treatment strategies, as well as predicting treatment response contributing to personalized medicine approach. Different models have different construct, face and predictive validity and they model different symptoms of the disease. The most prevalent models are the single prolonged stress, electric foot-shock and predator odor. Freezing as 're-experiencing' in cluster B and startle as 'arousal' in cluster E according to DSM-5 are the most frequently studied parameters; however, several other symptoms related to mood, cognitive and social skills are part of the examinations. Beside behavioral characteristics, symptoms of exaggerated sympathetic activity and hypothalamic-pituitary-adrenocortical axis as well as signs of sleep disturbances are also warranted. Test battery rather than a single test is required to describe a model properly and the results should be interpreted in a comprehensive way, e.g. creating a z-score. Research is shifting to study larger populations and identifying the features of the resilient and vulnerable individuals, which cannot be easily done in humans. Incorporation of the "three hit theory" in animal models may lead to a better animal model of vulnerability and resilience. As women are twice as vulnerable as men, more emphasize should be taken to include female animals. Moreover, hypothesis free testing and big data analysis may help to identify an array of biomarkers instead of a single variable for identification of vulnerability and for the purpose of personalized medicine.

A time to fight: Circadian control of aggression and associated autonomic support

The central circadian clock, located in the suprachiasmatic nucleus of the mammalian hypothalamus (SCN), regulates daily behavioral rhythms including the temporal propensity for aggressive behavior. Such aggression propensity rhythms are regulated by a functional circuit from the SCN to neurons that drive attack behavior in the ventromedial hypothalamus (VMH), via a relay in the subparaventricular zone (SPZ). In addition to this pathway, the SCN also regulates sleep-wake and locomotor activity rhythms, via the SPZ, in a circuit to the dorsomedial hypothalamus (DMH), a structure that is also known to play a key role in autonomic function and the sympathetic "fight-or-flight" response (which prepares the body for action in stressful situations such as an agonistic encounter). While the autonomic nervous system is known to be under pronounced circadian control, it is less apparent how such autonomic rhythms and their underlying circuitry may support the temporal propensity for aggressive behavior. Additionally, it is unclear how circadian and autonomic dysfunction may contribute to aberrant social and emotional behavior, such as agitation and aggression. Here we review the literature concerning interactions between the circadian and autonomic systems and aggression, and we discuss the implications of these relationships for human neural and behavioral pathologies.

Effects of social support and resilient coping on violent behavior in military veterans

Violence toward others has been identified as a serious postdeployment adjustment problem in a subset of Iraq- and Afghanistan-era veterans. In the current study, we examined the intricate links between posttraumatic stress disorder (PTSD), commonly cited psychosocial risk and protective factors, and violent behavior using a national randomly selected longitudinal sample of Iraq- and Afghanistan-era United States veterans. A total of 1,090 veterans from the 50 United States and all United States military branches completed 2 waves of self-report survey-data collection 1 year apart (retention rate = 79%). History of severe violent behavior at Wave 1 was the most substantial predictor of subsequent violence. In bivariate analyses, high correlations were observed among risk and protective factors, and between risk and protective factors and severe violence at both time points. In multivariate analyses, baseline violence (OR = 12.43, p < .001), baseline alcohol misuse (OR = 1.06, p < .05), increases in PTSD symptoms between Waves 1 and 2 (OR = 1.01, p < .05), and decreases in social support between Waves 1 and 2 (OR = .83, p < .05) were associated with increased risk for violence at Wave 2. Our findings suggest that rather than focusing specifically on PTSD symptoms, alcohol use, resilience, or social support in isolation, it may be more useful to consider how these risk and protective factors work in combination to convey how military personnel and veterans are managing the transition from wartime military service to civilian life, and at what point it might be most effective to intervene. (PsycINFO Database Record

Characterizing anger-related affect in individuals with posttraumatic stress disorder using ecological momentary assessment

This study employed secondary analyses of existing ecological momentary assessment (EMA) data to characterize hostile and irritable affect in the day-to-day experience of 52 smokers with, and 65 smokers without, posttraumatic stress disorder (PTSD). EMA monitoring occurred over a mean of 8.2 days, and participants responded to an average of 2.8 random prompts/day. Analyses included Wilcoxon rank sum tests of group differences, and path analyses of cross-lagged multilevel models. Participants with PTSD endorsed a significantly higher proportion of total EMA entries indicating hostile affect and irritable affect than did individuals without PTSD. Cross-lagged analyses indicated that over a period of hours, PTSD symptoms significantly predicted subsequent hostile and irritable affect, but hostile and irritable affect did not predict subsequent PTSD symptoms. Findings suggest that day-to-day exposure to PTSD-related trauma cues may contribute to chronically elevated levels of anger-related affect. Such heightened affective arousal may, in turn, underlie an increased risk for verbal or physical aggression, as well as other health and quality-of-life related impairments associated with PTSD. Clinical implications include conceptualizing anger treatment in the broader context of trauma history and symptoms, and specifically targeting physiological arousal and maladaptive hostile cognitions triggered by trauma reminders in patients with PTSD.