What is the characteristic behavior of individuals suffering from catatonia?

Individuals suffering from catatonia exhibit a characteristic behavior known as rigid posturing, where they may maintain a fixed position for extended periods. This is a key feature of catatonic behavior and can be quite striking. Those affected may not respond to external stimuli and can remain motionless in uncomfortable postures. This behavior is often seen in various psychiatric conditions, including schizophrenia and mood disorders.

In contrast, aggressive behavior typically manifests in different psychiatric or neurological disorders but is not a definitive characteristic of catatonia. Involuntary movement can occur in various conditions, including Parkinson's disease, but catatonia is more defined by the lack of voluntary movement rather than the presence of involuntary ones. Disorganized speech is associated with disorders like schizophrenia, but it does not align with the primary manifestations of catatonia, which is more about immobility and posturing than verbal communication. Therefore, rigid posturing is the most appropriate answer when identifying the hallmark behaviors of individuals with catatonia.