Marked motor abnormalities, generally limited to those occurring as part of a psychotic disorder. This term includes catatonic excitement (apparently purposeless agitation not influenced by external stimuli), stupor (decreased reactivity and fewer spontaneous movements, often with apparent unawareness of the surroundings), negativism (apparent motiveless resistance to instructions or attempts to be moved), posturing (the person’s assuming and maintaining an inappropriate or a bizarre stance), rigidity (the person’s maintaining a stance or posture against all efforts to be moved), and waxy flexibility or cerea flexibilitas (the person’s limbs can be put into positions that are maintained).
A pattern of behavior is identified, characterized by muscular tightness or rigidity, along with a lack of responsiveness to the surrounding environment. In certain individuals, this rigidity may alternate with episodes of heightened excitement or hyperactive behavior.