Mental capacity and autonomy are often understood to be normatively neutral? the only values or other norms they may presuppose are those the assessed person does or would accept. We show how mental disorder threatens normatively neutral accounts of autonomy. These accounts produce false positives, particularly in the case of disorders (such as depression, anorexia nervosa and schizophrenia) that affect evaluative abilities. Two normatively neutral strategies for handling autonomy-undermining disorder are explored and rejected: a blanket exclusion of mental disorder, and (...) functional tests requiring consistency, expression of identity, reflective non-alienation or lack of compulsion. Finally, we suggest ways in which substantivist alternatives to neutrality can be made more promising through increased transparency, democratic contestability of conditions for capacity and autonomy, and a historically sensitive caution concerning restrictions of liberty. (shrink)