How experiencing traumatic stress leads to aggression

Strengthened amygdala pathways increase aggression, may be targets for PTSD treatment

May 18, 2020

Science Daily/Society for Neuroscience

Traumatic stress can cause aggression by strengthening two brain pathways involved in emotion, according to research recently published in JNeurosci. Targeting those pathways via deep brain stimulation may stymie aggression associated with post-traumatic stress disorder.

The consequences of traumatic stress linger long after the stress ends. People suffering from post-traumatic stress disorder often display heightened aggression, caused by unknown changes in the amygdala. An almond-shaped structure nestled deep inside the brain, the amygdala plays an essential role in emotion, social behaviors, and aggression.

Nordman et al. examined how different amygdala circuits changed in male mice after traumatic stress. Two connections strengthened, resulting in more attacks on other mice: the circuitry connecting the amygdala to the ventromedial hypothalamus and the bed nucleus of the stria terminalis. The former modulates the frequency of attacks, while the latter controls the length of attacks. The research team then used low frequencies of light to stop the pathways from strengthening, preventing an increase in aggressive behavior. Deep brain stimulation may elicit the same effect in humans.

https://www.sciencedaily.com/releases/2020/05/200518145022.htm

Post-traumatic stress disorder linked to accelerated aging

May 8, 2015

Science Daily/University of California, San Diego Health Sciences

People with PTSD may also be at risk for accelerated aging or premature senescence, research suggests. The researchers noted that there has not been another study that links PTSD, a psychological disorder with no established genetic basis, to a basic biological process such as aging.

Writing in the May 7 online issue of American Journal of Geriatric Psychiatry, researchers at University of California, San Diego School of Medicine and Veterans Affairs San Diego Healthcare System suggest that people with PTSD may also be at risk for accelerated aging or premature senescence.

"This is the first study of its type to link PTSD, a psychological disorder with no established genetic basis, which is caused by external, traumatic stress, with long-term, systemic effects on a basic biological process such as aging," said Dilip V. Jeste, MD, Distinguished Professor of Psychiatry and Neurosciences and director of the Center on Healthy Aging and Senior Care at UC San Diego, who is the senior author of this study.

Researchers had previously noted a potential association between psychiatric conditions, such as schizophrenia and bipolar disorder, and acceleration of the aging process. Jeste and colleagues determined to see if PTSD might show a similar association by conducting a comprehensive review of published empirical studies relevant to early aging in PTSD, covering multiple databases going back to 2000.

There is no standardized definition of what constitutes premature or accelerated senescence. For guidance, the researchers looked at early aging phenomena associated with non-psychiatric conditions, such as Hutchinson-Gilford progeria syndrome, HIV infection and Down's syndrome. The majority of evidence fell into three categories: biological indicators or biomarkers, such as leukocyte telomere length (LTL), earlier occurrence or higher prevalence of medical conditions associated with advanced age and premature mortality.

In their literature review, the UC San Diego team identified 64 relevant studies; 22 were suitable for calculating overall effect sizes for biomarkers, 10 for mortality.

All six studies looking specifically at LTL found reduced telomere length in persons with PTSD. Leukocytes are white blood cells. Telomeres are stretches of protective, repetitive nucleotide sequences at the ends of chromosomes. These sequences shorten with every cell replication and are considered a strong measure of the aging process in cells.

The scientists also found consistent evidence of increased pro-inflammatory markers, such as C-reactive protein and tumor necrosis factor alpha, associated with PTSD.

A majority of reviewed studies found increased medical comorbidity of PTSD with several targeted conditions associated with normal aging, including cardiovascular disease, type 2 diabetes, gastrointestinal ulcer disease and dementia.

Seven of 10 studies indicated a mild-to-moderate association of PTSD with earlier mortality, consistent with an early onset or acceleration of aging in PTSD.

"These findings do not speak to whether accelerated aging is specific to PTSD, but they do argue the need to re-conceptualize PTSD as something more than a mental illness," said first author James B. Lohr, MD, professor of psychiatry. "Early senescence, increased medical morbidity and premature mortality in PTSD have implications in health care beyond simply treating PTSD symptoms. Our findings warrant a deeper look at this phenomenon and a more integrated medical-psychiatric approach to their care."

Barton Palmer, PhD, professor of psychiatry and a coauthor of the study, cautioned that "prospective longitudinal studies are needed to directly demonstrate accelerated aging in PTSD and to establish underlying mechanisms."

http://www.sciencedaily.com/releases/2015/05/150508082346.htm

Job Stress in Teachers Linked to Student Achievement

May 25, 2011

Science Daily/University of Houston

After 17 years of researching traumatic stress with war-afflicted populations (veterans and civilians) and job stress in the medical profession, Teresa McIntyre, a research professor in the department of psychology and the Texas Institute for Evaluation, Measurement and Statistics (TIMES), at the University of Houston (UH), decided to study another high risk occupation, middle school teachers in seventh and eighth grade.

"Middle school is probably the most difficult level to teach because student-teacher interactions are more difficult during this time, and this kind of difficulty in teacher-student interactions is a major source of stress for teachers at this level," McIntyre said.

"For students it's a time of adolescence and many changes developmentally, and that is going to affect the dynamics of learning, as well as the social relationships and climate in the classroom. It's going to affect the teachers as well. Our premise is that if the teacher is stressed, their behavior will be different with students, and they will perform differently with students."

http://www.sciencedaily.com/releases/2011/05/110525181422.htm