It sounds like your son has had sleep trouble before he got mononucleosis ("mono" for short). I'm assuming that illness is not the cause of the problem.

Your son may not be practicing good sleep hygiene. For example, is he distracted by having the TV or his cell phone on when he gets into bed? Is his room too hot or is he covering himself with too many blankets?

Assuming he is practicing good sleep hygiene, he may have a sleep disorder. There are many different kinds, and some are very common.

I would recommend that your son consult with a doctor who is an expert in sleep disorders. The doctor will try to figure out the nature of the problem.

The doctor will probably ask questions like this:

• Does your son have trouble falling asleep?
• Trouble staying asleep?
• Is he unable to fall asleep until 2am or 3am, and if an alarm clock or another person does not wake him, will he naturally stay asleep until late in the morning?
• Or, does he need to go to bed early in the evening, like 7pm to 8pm, but then awake at 3am to 4am and then not get back to sleep?
• At night, does he experience unpleasant sensations in his legs that wake him?
• Does he ever fall asleep uncontrollably during the day, at inappropriate times (like in the middle of a conversation or a meal)?
• Does he snore badly at night?
• When other people watch him sleep, are there times when it looks like he does not take a breath for 20 seconds or more?

The answers to these questions can help the sleep doctor make a diagnosis, and prescribe treatment.

Even though a sleep disorder is probably your son's main problem, his case of mono could be contributing to his problems. Mono causes considerable fatigue, which only adds to the fatigue caused by an existing sleep disorder. Usually the fatigue caused by mono lasts 3 to 4 weeks, and then the person returns to full health. However, about 10% of people who get mono continue to experience severe fatigue for as long as a year or longer after they get sick. So it is possible that the mono is still affecting your son, along with a more long-standing sleep disorder. A sleep doctor can help sort this all out.