Table 3

 Diagnostic criteria for serotonin syndrome

Reproduced with permission from Radomski et al. Med Hypotheses 2000;55:218–24.
• Increase in dosage or addition of a second serotonergic agent
• Plus 4 major symptoms or 3 major and 2 minor symptoms
Autonomic symptoms
    Major Minor
    HyperhidrosisTachypnoea, dyspnoea
Hypo- or hypertension
Mental symptoms
    Major Minor
    ConfusionAgitation, nervousness
    Coma or altered consciousness
Neurological symptoms
    Major Minor
    MyoclonusImpaired coordination
• Exclusions
    No recent introduction or dose increase of neuroleptic
    Other causes (e.g. infective, metabolic, endocrine, toxic) excluded
    No similar symptoms attributed to psychiatric condition before introduction of serotonergic agent