(Exercising Your Mind)
The first effects may be noticed within some days, but it may take one to three weeks to notice a pronounced change. It may take several months to derive full benefit.
–Edward Drummond, M.D.; “The Complete Guide to Psychiatric Drugs”, 2000
Clozapine may take a long time to be effective. Some people who do not respond after four weeks at a full dose will show a later response, and many people who initially have only a partial response will respond better after taking the medication for six months or more.
–Ronald J. Diamond, M.D.; “Instant Psychopharmacology”, 2002
Although antipsychotic drugs occupy dopamine receptors very quickly after administration, the maximal therapeutical (antipsychotic) effects are often delayed several weeks…
…The antipsychotic action may be secondary to other consequences in the brain that evolve over a period of several weeks.
Long term administration of antipsychotic agents leads to a downregulation of 5HT2 receptors that paralells in time course the therapeutic action of the antipsychotic drugs.
E.R. Kandel, J.H. Schwartz, T.M. Jessell; “Principles of Neural Science”, 2000