The serotonin syndrome as described by Sternbach <sup>33 Sternbach H. The serotonin syndrome Am J Psychol 1991 ;  148 : 705-713

Cliccare qui per andare alla sezione Riferimenti</sup> is a symptom complex resulting from an increase in the biologic activity of serotonin. The symptoms may include alteration in mental status, neuromuscular irritability, and autonomic instability. Constellations of symptoms thought to have resulted from increased concentrations of serotonin have been described as early as 1955 in a report that described positive Babinski reflexes, clonus, and twitching in a patient receiving iproniazid and meperidine. <sup>24 Mitchell R.S. Fatal toxic encephalitis occurring during iproniazid therapy in pulmonary tuberculosis Ann Intern Med 1955 ;  42 : 417-424

Cliccare qui per andare alla sezione Riferimenti</sup> In 1960, Oates and Sjoerdsma <sup>27 Oates J.A., Sjoerdsma A. Neurological effects of tryptophan in patients receiving a monoamine oxidase inhibitor Neurology 1960 ;  10 : 1076-1078

Cliccare qui per andare alla sezione Riferimenti</sup> described the indolamine syndrome that included altered mental status, ataxia, and lower extremity hyperreflexia in four patients receiving l-tryptophan and a monoamine oxidase inhibitor (MAOI). In that same year, Smith and Procop <sup>30 Smith B., Procop D.J. Central nervous system effects of ingestion of l-tryptophan by normal subjects N Engl J Med 1962 ;  267 : 1338-1341  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> noted euphoria, drowsiness, nystagmus, hyperreflexia, and ataxia after treatment with high-dose tryptophan. More recent literature has tended to implicate the tricyclic antidepressants (TCAs) and the selective serotonin reuptake inhibitors (SSRIs) as well as the MAOIs. This article outlines the identified causes of this syndrome, purported treatment options, incidence, pathophysiology, and the major diagnostic considerations.