Numerous food and drug combinations, also ‘legal highs', may precipitateserotonin syndrome, yet it appears to be rarely diagnosed. This may beexplained by diagnostic overshadowing when physical symptoms aremisattributed to mental illness. Some symptoms of serotonin syndrome(agitation, tremor and rigidity) overlap with presentations in mentalillness. Diagnostic confusion may occur in patients receiving polypharmacy,those receiving medications with previously unknown serotonergic propertiesor where unforeseen drug interactions occur. Acute medical presentationswith hyperthermia and clonus should prompt holistic review to exclude otherpossible aetiologies. Discontinuation of the suspected agent may avert anarray of possible serious outcomes.

Serotonin syndrome (serotonin toxicity or serotonin toxidrome) is apotentially serious and theoretically predictable reaction that appears tobe rarely diagnosed in practice in the UK. Some symptoms of serotoninsyndrome overlap with features of other presentations in psychiatry and thusmay be misattributed to mental illness (‘diagnostic overshadowing’).Further, there may be diagnostic dilemmas in patients on combinations ofdrugs, those receiving drugs with previously unknown serotonergic propertiesor where there are drug interactions. Prescriber vigilance and holisticreview of the patient, including the pharmacotherapy, may be helpful inavoiding progression of serotonin syndrome to more serious outcomes.