Each group had its own set of patches marking, at a minimum, the reason for being in the camp. Red was used for political enemies, green for criminals, blue for emigrants (non-Aryans such as Poles), pink for male sexual criminals (including homosexuals), and black or brown for "asocials" (including lesbians and Roma). Jews got a yellow star unless there was a supplemental reason for their being in the camp, which would result in a triangle of the color above plus an inverted yellow triangle underneath forming a corrupted Star of David. A Jewish criminal, for example, might wear a green triangle over an inverted yellow triangle.

It's not stated in the source below, but I believe that the mentally ill would be tagged as "asocial," which was something of a catch-all term for undesirables not described by the other groups.

Source: US Holocaust Museum