Mental, emotional and spiritual issues are not the easiest problems to reveal. We depend on what the patients tell us or what we can sense or suspect through body language and use of specific words during the consultation.
The body does not lie. If one can read it, it will tell what state it is in and what remedy, or at least what type of remedy it needs. There are windows of perception into the deepest mental situations even when the physical appearance seems to deny it: the bronzed athlete or the beautiful, lascivious woman can be depressed, anxious or schizophrenic. They will just hide it better than the common human.
The diagnostic methods of Traditional Chinese Medicine (TCM) can be used by homeopaths, especially in situations relating to very intimate problems that might be very difficult if not impossible for the patient to relate to the practitioner. Those methods allow pinpointing a group of remedies or a precise remedy without the need for the patient to perform a disturbing "psychological strip-tease".
This method has been, in my experience, the key to opening cases, unlocking suppressed and repressed memories, feelings and symptoms, allowing a faster and deeper analysis and eventually a correct prescription.