"I wouldn't dare tell no one. I didn't think anybody was going to believe me anyway."
She drank instead. And smoked marijuana and snorted cocaine. She fell out of the military and bounced from job to job.
Twenty-nine years after the 1983 assault, Fredericks has landed at the Baltimore VA Medical Center, where she says she is finally getting the services she needs.
The 48-year-old New Yorker is one of the growing number of veterans receiving treatment for post-traumatic stress disorder after suffering what VA officials call military sexual trauma.
One in five women screened by the Department of Veterans Affairs reports having experienced severe sexual harassment, attempted assault or rape during military service. VA officials believe the number of unreported incidents makes the actual percentage of women who have suffered military sexual trauma — also known as MST — significantly higher.
While MST is not itself a diagnosis, VA officials say the experience can lead to post-traumatic stress disorder, an anxiety disorder that can cause flashbacks, fear and isolation.
As the number of women seeking help from the VA health system has grown — female patients nationwide doubled to more than 310,000 from 2000 to 2010 — so has the incidence of PTSD related to sexual harassment or attacks.
Dr. Patricia M. Hayes, the VA's national director of women's health, likens military sexual trauma to incest.
"In the military, you rely on people in your unit to save your life, to serve together, to defend our country against the enemy," she said. "If some serious event like a sexual assault occurs, you've been betrayed by your unit and by the people that you've lived with and served with.
"So there are additional burdens of trauma that can occur because it occurred while in the military. And because you can't escape, except by going AWOL, you're living it 24-7."
The VA has military sexual trauma coordinators at each of its medical sites, and the agency has funded and conducted research on effective treatments.
National veterans groups applaud those efforts and praise the work of VA caregivers. But some say getting the VA's benefits administration to approve coverage for treatment of PTSD related to sexual harassment or attacks remains a challenge.
Within the MST program, "the counselors are very good," said former Marine Capt. Anu Bhagwati, executive director of the Service Women's Action Network, an advocacy group based in New York. "The problem really becomes about access and availability."
Bhagwati says VA figures obtained by the network show that while 53 percent of PTSD claims for combat are approved for coverage, just 32 percent of PTSD claims for military sexual trauma are.
"So you only have a 1-in-3 shot of getting your claim approved if you've been assaulted or harassed," she said.
Her group has sued the Department of Veterans Affairs for information about claims and approvals. Representatives of the Veterans Benefits Administration, the arm of the VA that considers claims, did not respond to messages seeking comment.
Bhagwati described her own experience in a letter last year to Veterans Affairs Secretary Eric K. Shinseki.
She wrote that she suffered depression and PTSD after being sexually harassed in the military. She told Shinseki that she gave the VA "overwhelming in-service evidence, statements from witnesses, my own detailed testimony, and several diagnoses from both non-VA and VA mental health providers, including a MST counselor whom I have been seeing for four years" — but her claim was denied.
The "rejection was devastating," she wrote. "It is only through the support of close family and friends that I continued to fight through my own betrayal, disappointment and trauma to get what I earned for my service."
The VA approved her claim last year — "four years, six lawyers, two representatives and one senator later," Bhagwati wrote.
Men also suffer military sexual trauma. One in 100 screened by the VA say that they experienced sexual harassment or assault during their service.
Although the rate among men is lower than for women, the numbers of men and women who report having experienced MST are similar — more than 58,000 women in 2010 and more than 49,000 men.
With the influx of female veterans coming into the VA, officials have tried to make local medical centers more welcoming to women. The VA has designated women's health providers at all 140 of its major medical centers and plans to place them at every outpatient clinic by the end of the year.
The women's clinic at the Baltimore VA Medical Center, where the number of female patients has tripled in the past 15 years, is scheduled to move to a larger space this spring.
"When I came here in 1995, women were a true minority," said Dr. Catherine Staropoli, medical director of the clinic in Baltimore. "And the system was not really set up to deal with their needs, historically. There's been a lot of culture change."
Dr. Sara Nett, the military sexual trauma coordinator at the Baltimore center, says the facility treats former service members for problems stemming from harassment or attacks free of charge — even if those former members are not eligible for other VA services.
"If a provider deems that the veteran is coming for either physical or mental health care that's related to MST, that session or that visit is not billed," she said. "All treatment for MST, whether it's physical or mental health conditions, should be free."
The Baltimore center is one of five in the national VA system that offers dual treatment for PTSD and substance abuse. The center has a 10-bed, mixed-gender, mixed-trauma unit and also treats outpatients.
The experiences of patients within a group may range from harassment to rape. Nett, a clinical psychologist, says it can be useful to bring them together to talk. "Often times people assume one type of assault is worse than another," she said. "But what we find is the individual reactions to different stressors vary tremendously.
"However, there are common themes, common symptoms and reactions that most people who experience threatening, harassment or assault will experience at one time or another."
After being assaulted, Machele Fredericks said, "my life became crazy." An air passenger specialist at an air base in England, she said she went from being a senior airman planning a career in the military to drinking and staying in bed or sometimes showing up to her assignment drunk.
She experienced flashbacks of the assault and suffered fear, anxiety and depression. She grew distant from her family and friends. She started smoking marijuana and eventually used cocaine.
"I was trying to soothe my feelings and forget," she said.
When she first sought help in the late 1980s, she thought her only problem was substance abuse. It wasn't until 2006 that she told a counselor about the attack more than two decades earlier and began treatment for PTSD.
Fredericks was referred to the Baltimore VA Medical Center late last year for the dual-treatment program for PTSD and substance abuse. She has one-on-one counseling with Nett and group sessions with other patients.
The treatment includes "in vivos," controlled excursions into the world to confront situations that have challenged her.
"I had to do the crowded elevators," she said. "It was very uncomfortable for me, because I don't really like people standing behind me. I had to do the crowded buses, and this weekend I had to go to the crowded malls. I definitely don't like crowded malls.
"I'm doing some things now that I didn't think I would be doing. The only way I did it [before] was with being high and using."
After she leaves the hospital, she wants to continue outpatient treatment. She says she will probably go back to New York and hopes to get work.
Does she feel as though she's getting better?
"It's hard," she said. "I still have my moments of helplessness. But right now, yes, I do."
Hayes, the national director of women's health, has studied military sexual trauma in Vietnam veterans and the links between MST and PTSD.
With treatment, she said, major recovery is possible.
"Now, no one would ever tell you someone's going to forget a sexual assault," she said. "But you can go from a memory that disturbs your whole life to a memory that you can live with. That's the goal for recovery."