Which symptom generally indicates a higher risk of Neuroleptic Malignant Syndrome?

Fever is the symptom that most commonly indicates a higher risk of Neuroleptic Malignant Syndrome (NMS). NMS is a serious and potentially life-threatening condition that occurs after the use of antipsychotic medications, particularly first-generation antipsychotics. Fever is one of the hallmark symptoms of NMS and typically presents as a significant elevation in temperature, often above 38 degrees Celsius (100.4 degrees Fahrenheit). This hyperthermia is due to a disturbance in thermoregulation that occurs in this syndrome.

In addition to fever, NMS is characterized by muscle rigidity, altered mental status, and autonomic instability. While incoherent thoughts, social withdrawal, and diminished speech can be observed in a variety of psychiatric conditions, they are not specific indicators of NMS. These symptoms may relate to underlying psychiatric disorders or other side effects of medications, but they do not have the same direct association with the risk of developing NMS as fever does. Thus, fever is the key symptom that clinicians monitor closely when assessing for NMS in patients undergoing treatment with antipsychotic medications.