@burcidi-- It depends on the specific corticosteroid and its potency. For example, I developed symptoms of psychosis when I was on prednisone 50mg/day. But the dose depends on the type of corticosteroid and it also depends on the individual.
Everyone is at risk of having corticosteroid induced psychosis. It doesn't matter if you have family members with psychological disorders or not.
And the psychosis is temporary. I only had psychosis symptoms for the first few days of my treatment and then the symptoms disappeared even though I was still on the drug. I think it has to do with our body adjusting to the medication.