Using antidepressants as a treatment for delusional parasitosis is probably not a good idea. After a series of law suits the FDA finally put a black box warning on antidepressants in 2004 stating that antidepressants can cause "suicidal thoughts". Thats right the FDA says antidepressants, drugs meant to stop bipolar/schizophrenic suicides, can CAUSE suicidal thoughts!
http://www.fda.gov/cder/drug/antidep...ts/default.htm