I seem to remember being very anti-Dr Comings in one of my pages on this site. I believe my exact quote was "Dr Comings was great in his day...now he's hopelessly inaccurate."
Ok, it seems I've been a bit unfair about the whole thing. It is true that he was talking about the wrong gene when he tried to pin down the GTS gene. And to be fair he was a bit mean to all people with Tourette's. But it also turns out that he was correct about the whole Drinking/Gambling/Hypersexual part of TS.
This is taken from the E-Move newsletter (without permission, unfortunately):
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1. The prevalence of pathological gambling, hypersexuality, and compulsive shopping in Parkinson's disease: A prospective study V Voon, K Hassan, M Zurowski, S Duff-Canning, A Lang, M Hallett, J Miyasaki PL01.003 (plenary session)
Compulsive behaviors are more common in PD patients on dopamine agonists than those on levodopa alone, according to this study. Questionnaires to assess pathological gambling, hypersexuality, and compulsive shopping were administered to 296 PD patients at a movement disorders clinic. Pathological gambling was seen in 10 patients (3.7%), including 6 males; hypersexuality in 7 (2.4%), all male; and compulsive shopping in 2 (<1%), both female. The prevalence of pathological gambling was double the number expected based on population-wide surveys; reliable figures for the other behaviors are not available. Compulsive behaviors were almost exclusively seen in patients on dopamine agonists, either alone or in combination with levodopa, without correlation to a specific agent. Hypersexuality was seen in 2 patients on levodopa monotherapy. "Larger multi-center trials are required to definitively determine the differences between PD patients and the general population," the principal author said. "Nonetheless, patients and caregivers should be aware of these commonly hidden behaviors."
2. Prevalence of pathological gambling in patients with Parkinson's disease O Suchowersky, C Lu, A Bharmal, S Kraft, Z Kiss S43.001, A313
Patients with a prior history of recreational gambling are at risk for developing pathological gambling after starting a dopamine agonist, according to this study. Chart reviews and interviews of 188 patients were conducted to determine presence of pathological gambling. Overall prevalence was 6% (12/188). All patients were on dopamine agonist combination therapy, with no single agent associated with increased risk. All patients with compulsive gambling had a prior history of well-controlled recreational gambling.
3. Pathologic gambling among Parkinson residents in north-central Florida HH Fernandez, MA Shapiro, YL Chang, SK Munson, CE Jacobson, RL Rodriguez, FM Skidmore, M Okun P01.150, A49 A survey on personality and gambling behavior was administered by mail or in person to over 500 PD patients. Of the 142 patients who returned completed surveys, pathological gambling was reported in 10, all of whom were on dopamine agonists. There were 21 non-compulsive gamblers. Compulsive gamblers were more likely to be younger, male, and have higher levels of anger or anxiety. |
Right, so this is Parkinson's disease. Big whoop. What does that have to do with Tourette syndrome?
Well actually the secret is in the phrase "Compulsive behaviors are more common in PD patients on dopamine agonists than those on levodopa alone, according to this study."
What these three studies are saying is that people on Dopamine agonists (make more dopamine) have these Gambling, Drinking, hypersexual behaviours while others don't.
And we all remember that Touretters have high levels of dopamine receptors in the brain, which give the same effect as a dopamine agonist.
It also mentions in the last article that those more likely to gamble will usually be male (TS more prevalent in males) who have anger and anxiety troubles (TS again).
So it looks like Dr Comings was right in that Dopamine was the contributing factor in these behaviours. I just didn't listen.
However, it seems that his gene 4q31 is not the one that affects dopamine. So he was sorta wrong too.