[PeterisP]

There are two major differences between mental diseases and typical physical diseases.

First, "sick days" generally are a policy for handling acute disorders; e.g. last week I didn't have disease X, today I do, and next week I'll be healthy again. You can't "wait out" a mental disease; taking a day or two off may reduce elevated stress levels but that is not the disease, the underlying problems aren't going to be solved when you come back.

The second issue is that many common physical issues are contagious, and there's a strong benefit for the employer and the society for sick people to "quarantine" themselves instead of going to offices and infecting coworkers and customers.

Mental diseases generally all are chronic and not contagious, and so they're similar in workplace (mis)treatment to things like arthritis or diabetes complications; things that don't map neatly to "x days to get cured" but instead need ongoing maintenance and unscheduled downtime forever.

[DanBC]

> First, "sick days" generally are a policy for handling acute disorders; e.g. last week I didn't have disease X, today I do, and next week I'll be healthy again. You can't "wait out" a mental disease; taking a day or two off may reduce elevated stress levels but that is not the disease, the underlying problems aren't going to be solved when you come back.

In the UK time off to manage a long term condition could be justified as a "reasonable adjustment" under the equality act.