Yes, in Canada it is allowed to take leave in any necessary circumstances but it is not mandatory every time that it is paid or unpaid. It depends on leave or firm also. As a person is dealing with something that causes stress or affects the mental conditions then in case he has to take leave and the employer also allowed them do take rest and will be back soon with recovery.
In some of the cases, we see that companies put a lot of burden on employee’s shoulders without any leaves or time for refreshments. In case the employee gets tired and starts taking a load of the work due to high pressure from the employer.
Stress can cause when people having a high workload but don’t have sufficient source and time to do. In such a case, one gets irritated but can do nothing because of the orders of the employer and tries to complete the anyhow also by hurting themselves mentally.
So as per the human or employee rights, they can take leave and no one going to deny them if there is a valid reason behind. If one is suffering from any disease or health issues, especially in case of the mental disorder means stress, depression then it’s a compulsion for the employer to give you or offer you leave. This is necessary to do because minor stress or depression can cause a chronic mental disorder.