Light treatment - making things worse?

My experience was the same as Yacht - first treatments were a lot shorter than yours seem to have been. I had PUVA treatment three times a week for 10 weeks and it was at least two weeks into the treatment before I got to 2 minutes. The treatment team tested my skin with a selection of doses on small areas before picking the starting dose (32 seconds if I remember correctly) and then increased slowly to around six minutes in the final week. Each time they would ask about any reaction to the previous dose and if I had experienced any redness or tenderness hold the dose the same that day instead of progressing to a higher dose. I found PUVA very effective, almost completely clear (plaque psoriasis) for six months after the treatment.