The Onion

Just a friendly reminder, documentation is crucial in any work environment, and do not believe any BS about great policies and employers that really care. Make sure you are fully aware of your legal rights, and if it's an option in your case, go through a legal procedure, rather than some internal "we'll work it out with a conversation and a handshake" process that your company will try and get you to go for.

I can't speak for anywhere but the US, but if you're having serious issues that might impact your ability to do your job/regularly show up, look into whether you qualify for any leave under the FMLA. Your mileage may vary, especially with smaller companies, but there are actually consequences for violating the law and/or retaliation under it. My experience at larger companies has been that they do not like to mess with it, and tend to farm compliance out to a third party to avoid any hint of impropriety. Again, there will certainly be differences, but across multiple companies, all my employer got from the process was a yes/no decision about whether I qualified, details of any duty restrictions applicable, when my claim was up for renewal and whether or not I marked my days of leave in compliance within the time limit established in the policy or not.

If they handle things in house, obviously don't trust HR. If an external company handles it, your employer shouldn't really know whether you're missing work because you've got cancer, you're insanely depressed, or whatever else the situation might be.

Regardless of how your company handles it, document everything to death, and make sure you're able to access your documentation in the event of losing the job. Should it come down to it, it doesn't matter how in the wrong your former employer was, you will not win any grievance or legal action if you haven't got the documentation to prove they did not meet their legal/contractual obligations.