I sort of see clozaril as a last resort kind of medication, given all of the blood tests involved (I think more than for Lithium) and other risks. I have heard it can be a real weight gainer, as well. Please do research both thoroughly, and measure the pros vs. cons. I will say that I've heard that clozaril does have a great reputation in terms of efficacy, but its cons are significant. However, like all medications, I've heard some people sing praises of clozaril, and dido for ECT.