It's no more scientific to reject evidence only because it is subjective. For a whole lot of psychological conditions that do not get to the extremes the only

It's no more scientific to reject evidence only because it is subjective. For a whole lot of psychological conditions that do not get to the extremes the only reasonable assessment we can do is whether the patient feels there is a problem, or exhibit indicators of distress in relation to the problem. Are you washing your hands so much it is OCD and a problem, or is it just a preference? At the margins - if you e.g. do it so much your hurt yourself - it becomes possible to argue it is objective, but for most people the answer purely comes down to whether or not it is subjectively a problem to them. That does not mean we can not systematically measure whether people report an improvement under varying conditions and using varying methods. It doesn't really matter if it is subjective - when the problem is that the patient feels there is a problem, then if the patient no longer reports feeling a problem, then unless you're prepared to assume that they are all in denial or lying, that is evidence of improvement even if it does not raise to the standard of evidence we would prefer. It would be unreasonable to overstate what that means, but equally unreasonable to pretend it provides no signal in the absence of higher standard evidence unless you can identify specific problems (lack of ability to reproduce would be one).