Risk factors

Some people are more susceptible to the drugs and supplements that cause serotonin syndrome than are others, but the condition can occur in anyone.

You're at increased risk of serotonin syndrome if:

• You recently started taking or increased the dose of a medication known to increase serotonin levels
• You take more than one drug known to increase serotonin levels
• You take herbal supplements known to increase serotonin levels
• You use an illicit drug known to increase serotonin levels