Waxy flexibility is a psychomotor symptom of catatonia as associated with schizophrenia, bipolar disorder, or other mental disorders which leads to a decreased response to stimuli and a tendency to remain in an immobile posture. Attempts to reposition the patient are met by "slight, even resistance", and after being repositioned the patient will typically remain in the new position. Waxy flexibility rarely occurs in cases of delirium. The presence of waxy flexibility along with at least two other catatonic symptoms such as stupor or negativism are enough to warrant a diagnosis of catatonia.
For instance, if one were to move the arm of someone with waxy flexibility, they would keep their arm where one moved it until it was moved again, as if it were made from wax. Further alteration of an individual's posture is similar to bending a candle. Although waxy flexibility has historically been linked to schizophrenia, there are also other disorders which it may be associated with, for example, mood disorder with catatonic behaviour.
Electroconvulsive therapy is often used as a treatment for catatonia. A study has found that catatonic patients suffering from waxy flexibility responded faster to electroconvulsive therapy, compared to patients with different catatonic symptoms.