The key to any injury under workers’ compensation is to prove that the symptoms or ailment you have are causally related to the work injury. This can be especially difficult with mental injuries.
The work injury does not have to be the only cause of your disability; it can be a combination of work related and non-work related injuries, but it must be a substantial contributing cause. For example, if you have depression because of pain from your injury and because of money stress, it is probably compensable. If your depression is only related to your money stress, which would be a mental-mental injury, it is not compensable.