Women who experience sexual assault are more likely to need medical care for mental health and stress-related problems in the year following the attack, new research suggests.

Researchers at Kaiser Permanente analyzed the medical records of 1,350 women in northern California who were sexually assaulted between 2009 and 2015. They compared the women’s use of health-care services and their diagnoses in the years before and after the assault.

The study also compared the victims’ records with those of other women of the same age and who attended the same medical facility but did not experience a sexual assault.

Sexual-violence survivors showed increased diagnoses for psychiatric and stress-related medical conditions such as post-traumatic stress disorder, insomnia, fatigue, physical pain and heart palpitations following the assault, the researchers found. The survivors also sought psychiatric and gynecological services more often than women who had not been assaulted, according to the study published in late May online in the journal Medical Care.

“Our study is, I think, to date the best evidence that shows an association between sexual assault, health problems and health care use,” said the study’s lead author Kelly Young-Wolff, a clinical psychologist and research scientist at the Kaiser Permanente Northern California Division of Research. “We need to be training clinicians in how to ask about sexual assault and respond appropriately.”

Diagnoses for posttraumatic stress disorder, or PTSD, saw the biggest spike following sexual assault. PTSD more than doubled from about 1 in 10 women seeking care to almost a quarter of sexual assault victims, according to the study. Psychiatric and sleep disorders also increased notably.

The findings confirm those of several previous studies on the issue, said Young-Wolff. However, the Kaiser study is the largest to look at the impact of sexual assault on health conditions and health-care utilization over an extended period of time and compared to a control group, she said.

Beth Hassett, Chief Executive Officer at WEAVE in Sacramento County, said the findings aren’t surprising. WEAVE provides crisis intervention services to survivors of domestic violence and sexual assault.

Hassett said the women her organization serves often experience mental and physical health problems for up to 10 years following an assault. These can include sleeplessness, suicidal thoughts, disordered thinking, flashbacks and self-medication with drugs or alcohol.

“We know that victims experience rape trauma syndrome, which is a type of PTSD,” she said. “It’s not a linear process. It can take months or even up to a year to really make it through some of those phases and getting counseling and help is what we recommend to people. Yet many people stuff their feelings and don’t want to talk about it and don’t reach out.”

Almost a fifth of women in the United States have been raped, and close to half have experienced some form of sexual violence during their lifetime, according to the federal Centers for Disease Control and Prevention. Hassett said it’s important for health providers and organizations providing crisis care to educate women about what to expect following an assault and where to seek help.

“I think a lot of people aren’t aware of the free support that’s out there and available to them,” she said. It’s important to “make sure people know that it’s normal to need help and that the trauma experienced during a crime like sexual assault is real and has an effect on the brain and people need assistance.”

More information on crisis services for sexual-assault survivors can be found at WEAVEInc.org and RAINN.org.