Say you had insomnia the other night and were able to fall asleep at 4, maybe 6, in the morning and there is almost no way you could go to work with that and perform. Would it be a valid reason to file for sick leave stating the above mentioned reason? Because I guess insomnia is a medical condition too.

The kinds of leaves I know off are casual, sick and annual. Now say, like alroc pointed out, you don't have to state that reason of your sickness and the company doesn't require it, and you had a rarely occurring sleepless night caused by insomnia. Would it be right to categorize the leave you took because of that, under "sick"ness?

  • For a single day or part of a day how detailed an reason do you need, and is proof required? Is your sick leave mingled with your vacation? Are there specific forms that are needed to be completed? Jul 9, 2013 at 10:39
  • 8
    I'm not sure why this is attracting close votes. This is a question I have wondered myself and suspect many other people have as well.
    – enderland
    Jul 9, 2013 at 11:34
  • @JoeStrazzere by filing I mean to say. You had insomnia and somehow managed to wake-up in the morning feeling crap(sleeplessness), call-up at work and say I am unable to come to work because I had insomnia last night. And if you don't manage to, then the following day you file in a sick leave for yesterday stating the reason why you couldn't appear for work Jul 9, 2013 at 11:54
  • @mhoran_psprep who can provide proof for insomnia that rarely occurs? And there is just a single form for sick leaves, you fill it stating the reason and submit Jul 9, 2013 at 11:57
  • I closed this post. See this Workplace Meta post for reasons why.
    – jmort253
    Jul 11, 2013 at 3:52

3 Answers 3


Depends on the industrial laws in your jurisdiction, but I'd say being unfit for work classifies as sick leave. Your employer may require and be entitled to receive a medical certificate from your GP, so you may pro-actively like to go talk to your GP about it if insomnia is something you experience regularly.

I should also point out that being fatigued, which you certainly would be if severely sleep deprived, can be quite dangerous. The risk of having an accident while driving, operating machinery or even crossing the street, is significantly higher than normal. Depending on your job, this may pose a risk to your colleagues.

For example, fatigue is a serious problem in the mining industry, which is why large mining companies often have regulations regarding fatigue (e.g. one company I worked at previously has a no-fault policy if you call in sick due to fatigue, you just don't get paid for that day).

Even if you drive a desk, chances are the work you produce while fatigued will be of a lower quality, or even counter-productive (you'll just have to fix all your mistakes the next day).

  • 3
    Yep, industry plays a part in this too. If you are a doctor, operate heavy machinery, or run a nuclear power plant, fatigue is definitely a valid reason for taking the day off!
    – Grant
    Jul 10, 2013 at 13:14
  • Just to point out, being unfit for work doesn't automatically mean sick leave. If I stayed up until 6am playing computer games maybe I should take the day off from operating a crane or performing brain surgery but that doesn't make it sick leave. This is the main problem with using insomnia as your reason since it is very hard to tell the difference between self inflicted sleepnessness (drank too much coffee, stayed up too late watching TV) and medical issues due to stress or something else. Unless you can get a doctor to diagnose you with chronic insomnia I think your chances are low.
    – Eric Nolan
    Jan 22, 2019 at 10:46

Unless your contract states that it is not a valid reason and you think that it will cause you to be inefficient and physically & mentally unable to perform your duties, then it should be acceptable.

Insomnia affects people differently. It's good to keep in mind if you do call in, because if the boss is someone who never had that bad symptoms from insomnia, s/he might not relate to you even if you feel poorly.


For doctors appointments I would specify doctors appointment. For anything else: insomnia (the original question), flu like symptoms, migraine... I would just label it not feeling well.

If the situation lasts more than a single day, or occurs more often than you are comfortable with, then see a doctor; and claim those hours for the appointment as a doctors appointment.

A longtime ago the company I worked for used the number of sick occurrences during the year into account when evaluating low level employees. The definition of sick occurrence required strict accounting of the reason for each absence:

  • Not feeling well, so leaving early or arriving a few hours late: one occurrence
  • Missing 4 hours for pre-surgical appointment, then 3 days for surgery and recovery, and two 3 hour post-op appointment 2 and 4 weeks later: one occurrence.
  • going to physical therapy 2 times a week for 3 months: one occurrence.

If you missed 3 days in a row, you needed a note from a doctor.

They were looking to make sure some employees weren't treating the 10 days of sick a year as extra vacation, or that they were using it to leave early on some Fridays, or were masking frequent hangovers as being sick.

Now that most companies have combined short term illness and vacation into one pool, the paperwork requirements have virtually disappeared. My current company time card system only asks for you to apply your daily allotment of your 40 hours a week to charge numbers, holiday, and annual leave. If an employee were going to miss multiple days in a row they have a short term disability program and a long term disability program. These extra programs do require additional paperwork and forms from the doctors office.

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