My dear there is NO need to get depressed!!
I completely understand what you are going through but medical science has made signficant advances.
Though the exact pathogenesis of psoriasis
is not completely understood but we have various treatment options.
I am unable to comment on the tablets as you have not mentioned what it is.
Newer treatment like - Biologicals have been used in treatment of psoriasis as well as psoriatic arthropathy and have good results.
Meet a dermatologist
with newer treatment options and dont feel disheartened.