Source: McConnel, James. "Mozart behaving badly," guardian.co.uk-culture-music-classical music, http://www.guardian.co.uk/music/2004/sep/01/classicalmusicandopera1, Spetember 1, 2004
Synopsis: The author of the article, who is a composer with Tourette Syndrome, offers his insights into the possible neurological conditions of Mozart, based in part on his analysis of documented evidence and Mozart's music (in fact, a Scandinavian scientist many years earlier had put forth a theory that Mozart suffered fro Tourette's, based on his analysis of Mozart's many letters, which were frequently scatological in nature). Mozart is well-documented as haveing a number of obsessions, such as clocks, cats, shoe sizes, and even his wife's safety (he was terrified to let her out of the house). Furthermore, there are numerous reports of him twitching, grimacing, and otherwise behaving oddly in formal situations. As with many people with Tourette's, Mozart was known (in his letters and socially) to take jokes and disgusting subject matter FAR beyond the limits of good taste, no doubt affected by his inablity to distinguish the synthetic boundaries of "good taste" as dictated by society. Additionally, Mozart's music indicates a strong desire to adhere to the rigid structures of old. In many Tourette Syndrome cases, there are secondary disorders that frequently exist in conjunction (the most common being Attention Defecit Hyperactivity Disorder and Obsessive Compulsive Disorder). Had Mozart suffered from this "grab bag" of disorders, it would go a long way towards explaining his odd social behavior and, in part, his outdated and esoteric love for the supremely-structured organization of counterpoint and fugue writing (musical veins which, at the time, were fading from style).
Reflection: It's very difficult for me to consider this article and NOT try and relate it to my own experience with music, social situations, and Tourette Syndrome. However, it's especially interesting that this is Mozart we're talking about; usually, most people consider him to be the "child prodigy" of legend, but few people would consider him to be one of the "eccentrics" like Beethoven or Bruckner. I can testify from personal experience that besides the obvious symptoms of Tourette Syndrome, one of the chief debilitating effects of the disorder is the inability to understand the unspoken conversational and activity-related parameters of social situations. In modern parlance, we would usually refer to this as "crossing the line," either in taste or general appropriateness, but it's very difficult when an otherwise well-functioning, properly-eductaed person simply doesn't KNOW where this invisible "line" is.
However, this in itself is not enough evidence to prove Mozart had Tourette Syndrome (or ANY medical disorder; there are plenty of "odd characters" who don't need a syndrome to be socially abnormal). I was more interested in the author's assertion that there exist written accounts of Mozart twitching, fidgeting, grimacing, and tapping his feet at inappropriate times. THESE gesticulations, moreso than any improper sense of social awareness, indicate the possibilty that Mozart suffered from Tourette's. The foot-tapping could be especially-damning; again, considering that Tourette's frequently comes with many secondary disorders, this extra movement could be the result of Tourette Syndrome, but more likely it is the result of ADHD and Mozart's subsequent restlessness and excessive energy.
In my experience, most people with Tourette Syndrome or similar neurological diosorders seem to show a propensity for all the things the author discussed: social inappropriateness, physical symptoms, making scatalogical or other similarly-inappropriate references far more frequently than the average gentleman. Also, I've noticed (like Mozart's alleged case) that many people with such disorders tend to thrive when performing tasks that require creating and following rules and organizational guidelines (although, the same cannot be said for following pre-existing guidelines, particularly when set forth by well-meaning grade school teachers or parents). This article by no means PROVES that Mozart had Tourette Syndrome, but it certainly opens the floor to discussion.