Subjects are 30- non-smoking outpatients with stable treated schizophrenia and 30 normal controls who do not have a major mental illness and who are matched for age sex and parental education. Subjects are randomized to one of 2 groups for order of receiving active and placebo patch, using a computer generated random number sequence. Randomization is concealed using opaque envelopes. Assessors and subjects are blind to group allocation.