surprise! animals suffer PTSD, too

…from Science Week:

PHYSIOLOGY: EFFECTS OF SOCIAL TRAUMA IN ANIMALS AND HUMANS

The following points are made by G. A. Bradshaw et al (Nature 2005 433:807):

1) Psychobiological trauma in humans is increasingly encountered as a legacy of war and socio-ecological disruptions. Trauma affects society directly through an individual's experience, and indirectly through social transmission and the collapse of traditional social structures. Long-term studies show that although many individuals survive, they may face a lifelong struggle with depression, suicide, or behavioral dysfunctions. In addition, their children and families can exhibit similar symptoms, including domestic violence. Trauma can define a culture.

2) How posttraumatic stress disorder (PTSD) manifests has long been a puzzle, but researchers today have a better idea as to why the effects of violence persist so long after the event. Studies on animals and human genocide survivors indicate that trauma early in life has lasting psychophysiological effects on brain and behavior. Under normal conditions, early mother-infant interactions facilitate the development of self-regulatory structures located in the corticolimbic region of the brain's right hemisphere. But with trauma, an enduring right-brain dysfunction can develop, creating a vulnerability to PTSD and a predisposition to violence in adulthood. Profound disruptions to the attachment bonding process, such as maternal separation, deprivation, or trauma, can upset psychobiological and neurochemical regulation in the developing brain, leading to abnormal neurogenesis, synaptogenesis, and neurochemical differentiation. The absence of compensatory social structures, such as older generations, can also impede recovery.

3) Elephant society in Africa has been decimated by mass deaths and social breakdown from poaching, culls, and habitat loss. From an estimated ten million elephants in the early 1900s, there are only half a million left today. Wild elephants are displaying symptoms associated with human PTSD: abnormal startle response, depression, unpredictable asocial behavior and hyperaggression. Elephants are renowned for their close relationships. Young elephants are reared in a matriarchal society, embedded in complex layers of extended family. Culls and illegal poaching have fragmented these patterns of social attachment by eliminating the supportive stratum of the matriarch and older female caretakers (allomothers).

4) Calves witnessing culls and those raised by young, inexperienced mothers are high-risk candidates for later disorders, including an inability to regulate stress-reactive aggressive states. Even the fetuses of young pregnant females can be affected by pre-natal stress during culls. The rhinoceros-killing males may have been particularly vulnerable to the effects of pre- and postnatal stress for two reasons. Studies on a variety of species indicate that male mammalian brains develop at a slower rate relative to females, but also that elephant males require a second distinct phase of socialization. As with females, male socialization begins during infancy with the mother and a tight constellation of allomothers. But in adolescence, males leave the natal family to participate in older all-male groups, a period coincident with a second major stage of brain reorganization identified in humans.[1-3]

References:

1. Clubb, R. & Mason, G. A Review of the Welfare of Elephants in European Zoos (RSPCA, Horsham, 2002)

2. Schore, A. N. Affect Dysregulation and Disorders of the Self (W. W. Norton, New York, 2003)

3. Slotow, R. et al. Nature 408, 425-426 (2000)

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