Picture this: you are in a room with a door on either end. The nearest one, through which you have entered, is still open. The other one is closed. Somehow, you know that when you close the nearby door, the lights will go out. You're scared. All you have to do is cross the room to open the other door, but even this simple action requires a tremendous leap of faith. 

No, we're not talking about death, but another big transition: high school graduation. "It's the fear that your life will not be in total control," says Bobbi Vogel, a family therapist. 

When a teenager leaves high school and goes to college, for the first time they will be in charge of their own laundry, meals, transportation, health, maybe even their own finances, and this can seem overwhelming. They will be the only one ensuring that they to get to class on time; they’ll be largely setting their own curfew. 

This creates a real ambivalence: they're excitedly looking forward to the freedom, the choices, the lack of instructions, but at the same time, this lack of structure can be scary. 

According to Vogel, another part of the fear is separation anxiety, particularly if a student is going to a school far away from home.

"Some teens have a fear that this is the first time they're going to be separated for a long period of time from their family and friends, their support system," she says. "What happens if I get into a funk or something and I want to come home and it's 3000 miles away, and Mom says I can only come home for Thanksgiving and Christmas and Easter?"

Megan Carlyle, 16, explains, "The thing I've mostly thought about is leaving my friends because my friends at my school are so… I don't know we just have these deep friendships that I would feel I was missing something if I didn't see these people every day."

Even though he's planning to live at home, high school student Jeff Stitch says, "When I think about it, I don't really want to graduate. Both because of the people I'm leaving behind and the unknown of what's out there." 

Some teens find a family away from home by joining a sorority or fraternity at college. Others make many friends in the dorm, where, after all, everyone is on equal footing in those first few lonely days. 

"But it's not as systemized as in high school where you start at a certain point and you end with the same amount of kids”, explains Vogel. 

According to a college counselor at a Los Angeles-area private school, graduation stress builds steadily throughout the career of a college prep school student. From ninth grade on, she points out, "They see college posters on the bulletin boards, college directors and deans come to visit each fall, college catalogs are in the library in a prominent place. It's part of life.”

"I'll walk across the courtyard and say `How are you doing?’ and they'll say, `I'm studying for the SAT.' A semester before, the topic of conversation was ‘What are you doing this weekend?’, now it's ‘What schools are you looking at?’ and ‘What kind of summer program are you going to?’."

Though 11th grade is the hardest year, that's when students prepare for the SAT and have to begin making important decisions, fear of graduation hits strongest during the second half of senior year. 

The fear is also about the failure of not getting into the college of their choice. Some very bright students start slacking off and, fully in denial, won't apply until the very last minute.Family problems may exacerbate at this time also. Dinner table talk is mostly about college. Both teens and their parents have been known to cry at such times. 

It may help teens to do something related to college, such as initiate a conversation with their parents, start working on an essay or bring home details of an upcoming college tour.  

The height of graduation fear occurs just before the big event, notes one counselor. That's when everyone starts talking about all the memories. When it's "the last assembly”, or the last whatever, it hits them: this time next year they won't be there.