It's not the flu or a head cold. It's not mono or strep throat. The dreaded disease of high school seniors is senioritis. Typically, senioritis strikes in the winter after college applications have been submitted or after final exams have been taken, but it can afflict seniors earlier in the year, too.

Seniors (and their parents and teachers) will recognize the signs and symptoms because those who have senioritis will stop caring about school. They might begin skipping class, or the quality of their schoolwork might diminish. Maybe they will stop studying for tests or forget to turn in homework, which will, in turn, cause a drop in their GPA. Seniors who are desperate for a cure have been known to lighten their course load by dropping academic classes that aren't necessary for graduation.

Ilene Abrams, college adviser at Berkeley High School in Berkeley, Calif., warns that making schedule adjustments after college applications have been submitted can be a big mistake. Colleges evaluate students based on first-semester grades, along with the assumption that students will complete all senior year courses, so any schedule changes can affect the admission decision, even after it has been made.

Abrams advises college-bound seniors to "stay in touch with colleges" by communicating any changes, whether it's a lower overall GPA or a dropped class. She says that students should also act pre-emptively and inform colleges about an anticipated low grade in the senior year so that admission officers can "tell the difference between senioritis and students who have just taken a really hard course load."

Abrams told me about students who had admissions decisions revoked when their GPAs dropped lower than those on the application or transcript. "At Berkeley High, most of the rescissions have been when the GPA dropped or when a student had a D or F. Many colleges will also not tolerate a drastic change in the class schedule either, especially when they've admitted students based on rigorous coursework in the senior year."

Senioritis can be expensive, too. Students who have been awarded merit scholarships — those based on test scores, a high GPA or a certain class rank — can have their financial aid either revised or revoked if the class rank or GPA falls below a certain threshold.

Some high schools, public and private, have a unique way of battling or even preventing senioritis. Self-directed research projects, community service work or off-campus internships, especially in the spring term, can serve to allow seniors to take control of their learning and provide opportunities for career exploration.