Editor's Note: (If you or someone you know needs help, call the national suicide hotline: 1-800-273-TALK.)
(CNN) Suicide contagion is a process in which the suicide of one person or multiple people can contribute to a rise in suicidal behaviors among others, especially those who already have suicidal thoughts or a known risk factor for suicide.
In 2018, after the deaths by suicide of American fashion designer Kate Spade and chef and storyteller Anthony Bourdain of CNN's "Parts Unknown," mental health experts said the high-profile suicides could possibly cause an increased risk of suicide contagion. Everyone should be aware of the risk factors related to suicide, they said.
"If they're already struggling with thoughts of depression or risk of suicide, they're already trying to get information about how other people are experiencing it," said John Ackerman, suicide prevention coordinator in the Center for Suicide Prevention and Research at Nationwide Children's Hospital in Columbus, Ohio.
"Especially when you've got high-profile people who are successful and who the world views as having a lot going for them and they die by suicide, it can generate feelings of hopelessness."
There was a 9.85% increase in suicides -- an additional 1,841 deaths -- recorded in the United States in the four months following comedian Robin Williams' death by suicide in 2014, according to a study published in the journal PLOS ONE in February.
That study was based on monthly suicide data from the US Centers for Disease Control and Prevention, dated from 1999 to 2015. The researchers then analyzed that data, taking a close look at suicide rates before and after his death.
"In the story with Robin Williams, you saw a 10% increase in deaths especially among middle-aged men using the method that was described," said Ackerman, who was not involved in that previous study.
"So we get concerned with celebrity suicides because when there's lots of attention and lots of specific reporting about it in a sensational way people may be more likely to identify with that person," he said.
Suicide contagion has also been studied within schools, military units, groups of friends, and families.
"Following exposure to suicide or suicidal behaviors within one's family or peer group, suicide risk can be minimized by having family members, friends, peers, and colleagues of the victim evaluated by a mental health professional. Persons deemed at risk for suicide should then be referred for additional mental health services," according to the US Department of Health and Human Services.
Globally, close to 800,000 people die due to suicide every year, which is about one person every 40 seconds, according to the World Health Organization. In 2015, more than 78% of those global suicides occurred in low- and middle-income countries.
In the US, suicide rates significantly increased in 44 states from 1999 through 2016, rising by more than 30% in 25 states, according to a new Vital Signs report published by the CDC on Thursday.
Nearly 45,000 lives were lost to suicide in 2016, according to that report. More than half of people who died by suicide did not have a known mental health condition, and various circumstances contributed to suicides among those with and without known conditions.
"Even though we need to do a really good job of supporting people who are already at risk of mental health issues, it goes beyond that. We need to make sure we're viewing this from a public health perspective and that we're making it easier for people to get resources, that we are reducing factors that contribute to suicide," Ackerman said.
Suicide rarely occurs "out of the blue," and there are risk factors, such as family history of suicide, family history of child maltreatment, previous suicide attempts, history of mental disorders, history of alcohol or substance abuse, feelings of hopelessness, among others.
Moreover, suicide can be preventable -- death should not be an acceptable outcome of depression, said Dr. Jeffrey Lieberman, professor and chairman of the Department of Psychiatry at Columbia University's Vagelos College of Physicians and Surgeons.
"When you have heart disease or when you have certain forms of cancer, there's a profile or a calculator of risk factors that's done. So with heart disease it's obesity, smoking, exercise, cholesterol, family history, and age. Same thing for suicide," Lieberman said.
"There's four disorders that have greatest increased risks of suicide: bipolar, depression, psychotic disorders like schizophrenia, and PTSD. Drug abuse or addiction is a potential complicating factor in all of them -- and in all of these conditions, death by suicide should never be an outcome," he said. "But when they don't get treated, some small proportion of them have the potential to harm themselves or will end their lives by suicide."
After the deaths of Spade and Bourdain, the nonprofit Mental Health America released a written statement from Paul Gionfriddo, its president and CEO. The statement noted that many people in the US do not have access to mental health services when needed.
"Death by suicide is the ultimate Stage 4 event in the progression of many mental health conditions, whether or not they have ever been recognized and labeled. People don't just go from being perfectly healthy one day to having suicidal ideation the next, just as they don't go from being perfectly healthy one day to having any other late-stage chronic condition the next," Gionfriddo said in the statement.
"In the aftermath of these highly visible tragedies, let's resolve not to sit back. Let's use them as an occasion to act. Let's reach out to, and engage with, others. Let's put in place the policies to address the root causes of suicide. And let's resolve -- finally -- to start bending the suicide curve in the opposite direction," the statement said.
The American Foundation for Suicide Prevention released a similar statement from its chief medical officer Dr. Christine Moutier.
"With recent high-profile deaths by suicide, this is a time to stand together and resolve to do more. Suicide affects all of us -- we all face challenges and have mental health to manage. We are working diligently to prevent suicide. The need for more research and a greater national investment in suicide prevention is clearer than ever," Moutier said in the statement.
The statement listed steps to help prevent suicide, including funding research to help identify people at high risk, increasing public awareness about the importance of effective mental health care, and funding the CDC's National Violent Death Reporting System to help better understand data at the time of a suicide and survey the problem.
"These clear steps can lower the national suicide rate," the statement said. "With all of us working together and by collectively making a massive investment in suicide prevention research, resources and quality mental health care we can and we will reverse the rising suicide rate."