Kate Johnson

April 19, 2012

April 19, 2012 (Arlington, Virginia) — Women with a history of childhood sexual abuse have changes in brain structure that may relate to genital sensation, a new imaging study shows.

Presented here at the Anxiety Disorders Association of America (ADAA) 32nd Annual Conference, investigators from the University of Miami in Florida found that early life trauma was related to much thinner somatosensory cortex, smaller hippocampal volume, and neurocognitive deficits.

"Is it possible that the somatic representation of the cortex for the genital area might actually be changed in women with [a history of] sexual abuse? It's a pretty far-out thought," principal investigator Charles Nemeroff, MD, from the University of Miami told conference delegates.

The study included 56 women aged 18 to 45 years with current major depression and either with or without a history of childhood sexual abuse, assessed by the Childhood Trauma Questionnaire.

Using standard cortical thickness analysis measures, investigators found a "marked reduction in the somatosensory cortical thickness area for the genital region in women with sexual abuse — the results were really quite significant," said Dr. Nemeroff.

The findings correspond with earlier work published by Dr. Nemeroff and colleagues showing that depressed women with a history of childhood abuse had an 18% smaller mean left hippocampal volume than nonabused depressed women (Am J Psychiatry, 2002;159:2072-80).

Uphill Battle

Expanding on that work, the investigators have also just published findings showing that early life trauma in general, including physical or sexual abuse or neglect, in both men and women is associated with neurocognitive deficits compared with control participants — with sexual abuse associated with signature deficits in visual working memory and executive functioning (J Psychiatr Res, 2012;4:500-6).

"We could actually, remarkably...separate out pretty clearly the neuropsychological profiles of the normal volunteers, the patients with neglect, and the patients with abuse, and the patients with abuse and neglect. It is really quite interesting," he said.

Taken together, the findings add neuroimaging and neuropsychological pieces to the psychiatric puzzle of the long-term effects of early life trauma in adult mood and anxiety disorders, said Dr. Nemeroff.

"The developing brain is vulnerable to insult," he said. "The human brain is not mature until age 23. It became clear to me that a great many patients with mood and anxiety disorders had early trauma histories, and they seemed to me to not respond as well to the conventional treatments as did other patients. This is really an uphill battle."

Dr. Nemeroff's early work with rodents and primates deprived of maternal contact showed an abnormal pituitary and adrenal response to stress that was subsequently confirmed in humans. This finding suggests that early life trauma sensitizes the nervous system and maintains it in a heightened state, he explained.

Asked by a conference attendee whether the thinner genital somatosensory cortex found in women with a history of abuse could be the result of decreased sexual activity as a result of abuse rather than the abuse itself, Dr. Nemeroff said that these women are not necessarily less sexually active than nonabused women.

However, he added, "they certainly show anhedonia in relation to sexual activity, and the cohort of patients with early life trauma also have much higher rates of adult trauma as well — so there's not enough information to answer that question."

Reversible?

"The question is how plastic is it? Can we reverse it?" asked Melissa Hunt, PhD, associate director of clinical training in the Department of Psychology at the University of Pennsylvania in Philadelphia, in an interview with Medscape Medical News.

Dr. Hunt agreed that the imaging findings could be consistent with sexual anhedonia.

"I work with this population a great deal. These women tend to be hypersexual because they are constantly putting themselves in situations where they are re-victimized," she said.

"They often begin to dissociate when someone expresses sexual interest, so what they essentially experience is that they're being raped constantly except that they're never actually saying no."

She added that Dr. Nemeroff's findings of reduced cortical thickness could potentially be useful in measuring treatment response.

Dr. Nemeroff disclosed owning stock, stock options, and equity with CeNeRx, NovaDel Pharma Inc., PharmaNeuroBoost, Revaax Pharma, and Concept Therapeutics. He is on the Board of Directors of the American Foundation for Suicide Prevention (AFSP) and NovaDel Pharma Inc. He is on the Scientific Advisory Boards for CeNeRx, NovaDel Pharma Inc., PharmaNeuroBoost, AFSP, the National Alliance for Research on Schizophrenia and Depression, and Takeda. He holds patents on a device for transdermal delivery of lithium and on a method for assessing antidepressant drug therapy via transport inhibition of monoamine neurotransmitters by ex vivo assay. Dr. Hunt has disclosed no relevant financial relationships.

Anxiety Disorders Association of America (ADAA) 32nd Annual Conference. Session 316R, presented April 13, 2012.

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