It is a common view that if Fred could not have been reasonably expected to know that what he is doing is wrong, if his ignorance of the wrongness of the action is not his fault, then Fred is not culpable for what he did—though he may be responsible in some way other than culpability (e.g., obliged to make restitution). I am inclined to a much stronger view. If Fred does not believe that what he is doing is wrong, then Fred is not culpable for that action. This is true even if Fred knew that the action was wrong and brainwashed himself out of the belief in its wrongness precisely to escape culpability for the action. Of course, in such a case, he does not escape culpability for brainwashing himself with that end in view. But the wrongful deed that was the subject of his brainwashing does not add to his guilt. He is guilty only for the self-deceit, and he is guilty whether or not he goes on to do that further deed.
I do not know that I've met anybody else who endorsed that stronger view. But it is, I think, an unavoidable consequence of a strong denial of moral luck. Suppose one thinks, as one should, that, ceteris paribus, one incurs no more objective guilt by committing a murder than by attempting a murder. Then consider the following means of attempting murder: Fred hypnotizes himself into killing Patrick. In this case, the act of self-hypnosis is the act of attempting murder, since one does not act under hypnosis (I stipulate). If under hypnosis he kills Patrick, he has committed murder. But his murderous act was the act of committing self-hypnosis—it was an act done with the end that Patrick should die. (If this isn't clear, suppose that Fred hypnotizes Sally into killing Patrick. Then Fred's hypnotizing Sally is an act of murder, and Sally does not act in killing Patrick. But the same is true if Fred is both hypnotist and subject of hypnosis.) So if we deny moral luck, we have to say that he is no more guilty when he succeeds in hypnotizing himself into killing Patrick than when he does not succeed.
Now, suppose that instead of hypnotizing himself, Fred brainwashes himself into believing that he ought to kill Patrick, in order that Patrick may die. The act of self-brainwashing here is also an attempt, perhaps successful and perhaps not, to bring about Patrick's death. (This is really clear in the case where Patrick brainwashes Sally.) Therefore, Fred is guilty of a crime equal to murder, even if the attempt at self-brainwashing fails or succeeds but later on he doesn't carry through the deed. Suppose it all succeeds, though. Then Fred's act of killing Patrick is not a guilty act, though it is a wrongful one. Here is why. Fred has already committed an act equal to murder—the self-brainwashing with the intention that Patrick's death should result. If Fred's act of killing Patrick is a guilty act, then he has committed two acts equal to murder—he is doubly guilty. But that is multiplying guilt beyond necessity. Fred indeed is guilty of two things, but surely not of two acts equal to murder: he is guilty of one act equal to murder (namely, the self-brainwashing with lethal intention) and one act where he sins against himself (namely, by destroying his moral sense through self-brainwashing)—and he is guilty of both whether or not he goes on to kill Patrick.