Warning Signs of Serotonin Syndrome

The following are warning signs of serotonin syndrome (ss). Diagnosing SS is challenging, even for medical professionals. Not all signs need be present for SS to exist, and other symptoms may present at the same time as SS. If in doubt, get to emergency care immediately and disclose all legal and illegal drugs, and all supplement and dietary habits to the medical professioals.

SS may be present if:

  • There is a change in mental status, such as agitation, anxiety, confusion and unresponsiveness;

  • neuromuscular symptoms, such as muscle spasms, tremors and shivering;

  • rapid heart rate;

  • profuse sweating;

  • high blood pressure;

  • nausea;

  • vomiting;

  • diarrhea.


A common diagnostic tools for professional is shown in the image below. These test are only suitable for medical professionals, and are provided so you better understand the test a medical professional should be performing to test for SS.

Any of the following suggests SS while on MDMA according to this info graphic:

  • Tremor (involuntary quivering) plus (overactive or over responsive reflexes).

  • Spontaneous involuntary, rhythmic, muscular contractions and relaxations (see here)

  • Muscle rigidity plus body temperature above 100.4 PLUS (i) ocular clonus OR (ii) inducible clonus.

    Ocular Clonus: People who have taken MDMA often experience ocular clonus and will be quick to identify it: imagining the eye connected to the end of a long spring. Every time the patient voluntarily moves their eye, there is a back and forth wobbling for a few seconds before the eye stabilizes at a point of gaze.

    Inducible clonus is an involuntary, rhytmic, musucal contrations and relaxation in response to a simulation.

  • Agitation or unusual sweating PLUS ocular or inducible clonus.

fig1serotonin.jpg