House on the Hill by Kevin Coyne - in fact any number of his earlier songs where he was fresh from working as a psychiatric social worker - is a good example of non-stigamatising songwriting about mental illness. Also check out the UK organisation 'Mad Pride' and the compilation album they put out a few years back, 'Nutters With Attitude'.

Many (but by no means all of the songs) listed on this thread are using mental distress as a titillating, sensationalist or novelty topic and are in practice contributing to the stigmatisation and social exclusion of people with mental health needs, so should be just what Tony needs for his students. I'd suggest the Kevin Coyne and Mad Pride stuff as an antidote to this in order to cleanse the old mental palate at the end of the session!