Serum haloperidol levels in Gilles de la Tourette syndrome

The present study has demonstrated that Tourette patients therapeutically respond to remarkably low levels of haloperidol. These results lend support to the hypothesis of a supersensitive dopaminergic receptor site as the pathophysiologic defect in Tourette syndrome. Of interest is the unusual sensitivity of the Tourette patient's receptors to butyrophenone blockade. This unique property produces both a therapeutic response as well as an increased tendency toward dysphoric side effects. Recent studies have demonstrated three separate dopaminergic receptor sites: Type 1, a haloperidol-insensitive adenylate-cyclase-related postynaptic receptor; Type 2, a haloperidol-sensitive postsynaptic receptor and a presynaptic autoreceptor. The authors speculate that the response of Tourette patients to drug therapy is based upon changes at the Type 2 receptor, although the possibility still exists that haloperidol might be altering dopaminergic transmission through blockade of presynaptic autoreceptors.