(CNN) -- A state senator stabbed, his son dead from a gunshot wound.
A tragedy, to be sure. But for many parents of children struggling with mental illness -- a wrenching experience in itself -- it can be a truly chilling scenario.
Virginia State Police on Tuesday said Sen. Creigh Deeds was stabbed after an altercation with his 24-year-old son, Austin "Gus" Deeds. The younger man then shot himself, authorities said.
Austin Deeds withdrew from The College of William & Mary last month after being enrolled off and on since 2007, according to a statement from the school.
The Richmond Times-Dispatch reported Tuesday that he had received a mental health evaluation under an emergency custody order on Monday, but was released because no psychiatric bed could be found in the area.
The vast majority of young adults with mental health issues do not become violent, although young adulthood is typically when symptoms of mental illness, including schizophrenia or bipolar disorder, surface, experts say.
However, parents and others can be on the lookout for warning signs of violence.
It can be difficult to predict, said Daniel Davis, a forensic psychologist in private practice in Columbus, Ohio.
But "over the past 20 years, perhaps especially the past 10, we've gotten a lot better at being able to pick up what would be risk factors for aggressive and violent behavior in youth," he said.
Some of those red flags might include:
Increased anger, suicidal thoughts
A young adult might be increasingly angry or talk of suicide, Davis said, making statements such as "the world would be better off without him" or that his life doesn't matter.
They may develop an increasing fascination with violence or aggression, and may show contempt for others.
Moodiness, depression, substance abuse
Adults may isolate themselves and withdraw from friends and peers, experts said. Their school or work performance may decline and they may become paranoid. They may begin abusing alcohol or drugs, or their use may increase.
A sign of a psychotic disorder may be the development of seemingly odd interests and beliefs -- in UFOs, for instance, or predicting the future, according to CNN mental health expert Dr. Charles Raison.
"It is not necessarily predictive of aggression, but these are all things that should not be ignored and should be responded to," Davis said.
A person may lose sleep because of brain chemistry changes, Dennis Embry, president and senior scientist at the Paxis Institute in Tucson, Arizona, told CNN in 2011.
In the case of psychosis, their appearance may actually change and become stranger and disturbing, according to Raison.
Any of these factors are more concerning, said Davis, if a person has a history of aggressive behavior or substance abuse -- and if they have access to weapons.
"Typically, the rate of violence among the mentally ill is actually lower than the general population," he said, but substance abuse can exacerbate existing symptoms such as paranoia, isolation or impulsiveness.
What to do?
There is hope, experts said.
"We have good evidence-based treatments for these sorts of issues," Davis said. Those might include cognitive behavioral therapy, substance abuse treatment or medication.
Parents or friends can attempt to discuss problems or symptoms matter-of-factly with a young adult. If they are unwilling to seek help, "consult a mental health professional yourself to see if they have suggestions" or specific guidelines for actions you can take, Davis said.
Reach out to a mental health center or your primary care doctor. If the child is in college, consult the college's counseling center. Groups like the National Alliance on Mental Illness may be able to provide referrals.
Although state laws vary -- and beds are scarce, as seen in Deeds' case -- people can usually be hospitalized against their will if there is clear evidence they intend to commit violence.
"In my experience, such hospitalizations can often short-circuit the danger and get people into much-needed treatment," Raison wrote. "Of course, this is not always the case. But it is the best we can do, and it is a lot better than nothing."