All jobs are stressful to some extent. Most people are more productive when there is a good match between the employee’s needs and his/her working conditions, whether or not the worker is suffering from a mental illness or not.
A myth related to this says .. that people with mental illnesses cannot tolerate the stress of holding down jobs. I think that this depends on the person’s illness as well as the job. Once again, if we are not judgemental and give the person a chance, he/she might even surprise us.