"It's not just the ongoing psychological impact victims have to deal with, there seems to be actual biological changes that occur when you've experienced repeated childhood trauma."
The pain and illness can be real or imagined, where psychological distress presents as physical symptoms, she said.
The psychiatrist spoke of one patient, a woman who had experienced terrible and persistent oral rape as a child.
"She now has major difficulties eating certain types of food, or tolerating eating at all."
Another woman, who was in her 20s, presented repeatedly to her doctor with stomach aches and headaches.
It took 18 months for the woman to reveal she had been raped.
"That was bad enough, but when you bothered to look back to what else had happened in her life, you learn her father was a violent man who spent much of her childhood in prison, and her stepfather sexually abused her from the age of 8 to 13," Dr Atchison said.
"The only sexual relationship she ever had apart from her stepfather was the man who raped her," she said.
The woman's stomach pain and headaches were eventually recognised as somatisation: physical manifestations of her psychological trauma.
"When you put it all together there's no wonder that her abuse resulted in such persistent physical symptoms."
Between 7 and 36 per cent of females have been the victims of serious child abuse, and 3 to 29 per cent of males, international epidemiological studies suggest.
But only 38 per cent of victims report the abuse – either because they're too young, they want to protect the offender or they worry they won't be believed.
Patients whose child abuse manifests as physical symptoms could be suffering from complex PTSD, Dr Atchison said, a contentious diagnosis that is being considered for inclusion in the psychiatrist's bible, the DSM-5.
Like PTSD, patients who are subjected to frightening, often life-threatening events re-experience it through nightmares, intrusive thoughts and flashbacks.
But C-PTSD, often misdiagnosed as borderline personality disorder, is more specific to experiences of serious and repeated trauma when a child is going through emotional and physical development, she said.
Another patient, a 45 year-old man with terrible back pain, found opiates gave him little relief. His doctors had focused on his physical symptoms.
"But when you bothered to talk to him [we discovered] he had a father who would beat him and not his two siblings, for absolutely no reason. He couldn't understand why that was happening all the way through his childhood," Dr Atchison said.
Once the man could talk through his trauma, his treatment team focused on stepping down his drug use and trying to reframe his body as a healthy tool rather than a damaged object, she said.
Although the underlying mechanisms are not fully understood, researchers have suggested that trauma whittles away the body during the critical stage of hormonal, neurological and immune system development.
Repeated trauma is thought to affect the central nervous system, endocrine system, and the body's stress response.
Prolonged cortisol elevation triggered by repeated traumatic events can cause withdrawal and dysphoria that protects a victim during the abuse. But sustained and repeated trauma can lead to hypocortisolism, damaging the immune system, Dr Atchison said.
Another patient, a man in his 60s, had spent a traumatic period of isolation in a full body cast at a hospital in the UK separated from his family and with little human contact when he was six years old.
"He remembers purposefully soiling his cast so he could get his cast changed and actually talk to someone.
"Over the years, he had struggled with poorly controlled type 2 diabetes, hypertension and chronic headaches, that didn't respond to treatment," Dr Atchison said.
The unresponsiveness was a red flag for C-PTSD, she said.
"If doctors suspect a patient has somatisation, they should take a developmental history, and ask with they had experienced abuse and trauma growing up.
"The load of childhood trauma may help explain the chronic pain they find so difficult to manage."