it looked like parkinsonian side effects. so people began to get some insight on how they worked. they worked through the dopaminitric system and blocked certain reseptemberers. we'll discuss this later on. so using that idea, people tried to develop drugs that don't have those side effects if. and that's what's called the second generation of anti-psychotics. >> let's turn to the genetics. understanding the genetic basis for schizophrenia. >> well, the first thing to say about that is that the highest risk you would ever have of developing schizophrenia is if you had an identical twin with schizophrenia. then you would have about a 50% chance of developing that disorder in your life. and as's true even if you are not raised in the same family. even if they are adopted twins raised separately it tells you there is some sort of a genetic risk, much higher tn the risk to the population, about 1%. if also tells you those genes can't be acting alone because it is not 1 --% either there are interactions between genetic risks and the environmentment a big piece of progress has happened