I would argue that the true self, including one's 'true' feelings, are the summation of the whole person including one's capacity to make choices about what you do or say and why you do so, not just what you show when your control mechanism, capacity and reasoning are impaired by drugs or alcohol. To argue that you only see a person's 'true' feelings or self when the checks are off is reductionist and creates a highly skewed perception of selfhood - we are so much more than this.

re the friend, it sounds like this is an aspect of herself certainly, or at least certain inclinations, but in itself no truer a representation of who she really is than the aspects that maintain values and behaviour when her functioning and capacity are not impaired.