Comment by safety1st

I am only entreating you to be accurate about the terminology used. Due to its historical use by psychologists the term mental illness is generally thought to be synonymous with mental disorder, which is the modern term that refers to a specific illness classified in the DSM-IV which psychiatrists may diagnose. There are only so many of them, and they are defined, and they are diagnosed by name by doctors. To me it is not a matter of sensitivity, and certainly not one of underplaying, but of precision. If you want to diagnose Matt you need to tell us which DSM-IV disorder he is afflicted by and what your authority for the diagnosis is. It sounds like that was not your intent so it would be more clear if you referred to his psychological distress, or sure, "has come unglued"/"lost his mind," or just said he seemed mentally unwell. None of these imply that you're a doctor making a formal diagnosis. They also do not imply that the problem is somehow lessened -- you just aren't mapping it to a definition in the DSM (which ultimately implies some amount of endorsement for treatment, including specific therapies and drugs depending on what you diagnosed). There are unfortunately people out there who will read your comment and take it to mean that a doctor actually diagnosed Matt.