Many parents grapple with their underperforming grown offspring. A 42-year-old son may be unable to hold a job and continue asking his folks for money. A 30-year-old daughter continually hooks up with unstable partners, then moves home with her toddler in tow.

These low-functioning adult children don’t require hospitalization. Most haven’t been diagnosed as having disabling psychiatric illnesses. On the surface, they appear to be capable of managing their own lives. Still, they fail to thrive once they’ve been launched, often relying on the services and bank account of mom and dad.

The concept of functioning implies the ability to support oneself for an extended period of time. At the very least, a person must be able to find and hold a job, establish a stable residence and successfully manage his or her finances.

Low functioning takes different forms in different people. One person may be completely unmotivated and be happy perennially couch surfing on various buddies’ sofas. Another may get belligerent and make threatening phone calls and gestures. A third may use horrible judgment, lending flaky boyfriends money to buy drugs. A fourth may be an alcoholic and get fired from every job.

Functioning is separate from intelligence. A young woman may score high on an IQ test yet be so emotionally unstable that she can’t show up to work or pay her bills. Meanwhile, her less academically gifted sister has steady employment, a boyfriend and her own apartment.

The inability to function normally shows up early in a child’s life. Kids have problems paying attention in grade school. They’re unable to get along with classmates. They don’t complete homework assignments. They’re in trouble with school officials for smoking pot in the restrooms.

Parents do their best to address these early problems by getting tutors or attending meetings with children’s teachers and principals.

But once these low-functioning kids reach adulthood, mom and dad quickly run out of options. They may pay a son to stay in college or set him up with his own business. They may repeatedly lend him money or bail him out of jail. Yet these endeavors seldom solve the problem. Junior repeatedly fails to thrive.

To make matters worse, parents frequently find themselves at odds. They may blame each other for causing the problem. They disagree about what to do. Their well-laid plans for a pleasant, financially solid retirement are in jeopardy because their daughter won’t move out of the house.

What these conscientious folks need to realize is that they didn’t cause the problem and that there’s little they can do to resolve it. Yes, they can try various options. They can speak with experts or offer to pay for therapy. Still, some children simply fail to stay airborne no matter how hard mom and pop try.

TRY THESE TIPS FOR LOW-FUNCTIONING ADULT CHILDREN IN YOUR FAMILY

• Work together with your partner, and stop viewing each other as enemies. You already have a low-functioning adult child.

• Don’t give money to low-functioning adult children. An extra $1,000 seldom solves the problem. And they’re unlikely to spend it wisely. If you must give them money, do it for a specific purpose and pay the provider directly (i.e. pay college tuition directly to the school).

• Never bail them out. Resist the temptation to rescue them from their mishaps. That reinforces bad decisions and behavior. Plus, it keeps you needlessly in the loop. They got into the problem; they can get themselves out.

• Never tolerate abusive behavior. Hang up if they make threatening phone calls. Call the police if they become aggressive.

• Create a plan. Discuss with your partner what you’re willing and unwilling to do. Include the children in the discussion if it’s appropriate. For instance, you may decide to pay for your daughter’s drug rehab program. But you are not going to buy her a new car.

• Get expert advice. A professional may help you discern an underlying cause of your child’s problems or develop a strategy for managing her. Don’t hesitate to ask.

• Know you’re not alone. Many parents deal with this. Your situation isn’t unique. Let go of your shame and isolation. That only saps your emotional reserves.

• Be strong. Low-functioning adult children are emotionally and financially draining. They elicit pangs of guilt. They keep households on edge. Don’t cave in. Stick with your resolve. Both you and your children will benefit from your behavior.

Linda Lewis Griffith is a local marriage and family therapist. For information or to contact her, visit http://lindalewis griffith.com.