How bias creeps into clinical trials of psychotropic drug development

In the clinical trials for producing a psychotropic drug,it's observed that they do not adequately blind the studies.So the patient even responds to a placebo.Which means that  the psychotropic drugs are only a shade better than placebos. And if a patient is already on a psychotropic drug and enters the clinical trial then adequate time to eliminate the drug from the body is not allowed to make them ready for receiving the new drug. Which means they are only showing response to the previous drug. Not the new one being developed. But they record it as if the response is to the new drug. And this where the psychiatry patient gets cheated because he is getting an old wine in a new bottle.