Welcome Wombat, I don't know about squalene.
I used to work for an accuponcture and I saw a patient with psoriasis and she was on the edge to kill herself (she confessed to me a week later on her next visite) after her first treatement, she was very pleased with the result, you should give a try. Good luck!
Welcome to SCT. My mum also suffers from psoriasis. Try bathing in sea water or apply sea water to the affected areas as this is extremely beneficial for psoriasis. My mum's gp advised her to do the same. Also, try applying aloe vera gel.