Raising kids is stressful when children are young, and again when they go through the teen years. But by their early 20s, parents should be able to take a deep breath and congratulate themselves on a job well done. Ideally by this time, your children have embarked on a career path and are ready to stand on their own as full-fledged adults.

See also: Strategies to help your kids in tough job market.

However, the reality is that in many families, it's not quite so simple. These so-called "emerging adult" years are a time of heightened risk in a variety of ways. Consider: Substance use and abuse peaks at age 21 to 22, including binge drinking, marijuana use and other drug use; serious mental health disorders such as schizophrenia and bipolar disorder typically appear for the first time in the late teens or early twenties; a host of other mental health disorders increase sharply from adolescence to emerging adulthood, most notably major depression and anxiety disorders; eating disorders are highest among young women in their 20s.

Helping children in their 20s and beyond is a lot more complicated than dealing with younger kids. For one thing, teens typically live in the same house, so parents have a good sense of what's going on in their lives. Also, parents can arrange to get them help, whether the children see themselves as having a problem or not.

However, young adults are often living independently, and by this life stage their parents' knowledge and control of what's going on with them may be limited. Even for older kids who are still in the household, their parents can't legally require them to get help if they don't want it.

Nevertheless, there are important steps parents can take if they believe their grown children are in serious trouble. "Start by recognizing that you can't fix the problem by yourself," advises Jennifer Tanner of Rutgers University, who conducts workshops on mental health in emerging adulthood for parents, mental health professionals and researchers. "If it's a serious mental health issue, it's going to require professional intervention." The best thing parents can do is try to provide a bridge between their grown child and someone who has the knowledge and training to help them. "Try to see your role as parent as a service connector between your young adult and a professional," says Tanner. "That's how you can be most helpful."