demented
This term carries a heavy clinical weight when describing cognitive decline, implying a permanent loss of mental faculty. In medical contexts, it is a direct descriptor of a pathological state of confusion and memory loss. In a non-clinical sense, the word describes a state of frantic or manic instability. It suggests a loss of control that is frightening or erratic, often used to describe laughter, screams, or behavior that seems completely detached from reality.
Meanings
Suffering from dementia or a severe mental disorder that impairs cognitive function.
"The elderly man became increasingly demented in his final years."
Behaving in a wild, irrational, or uncontrolled manner, often due to extreme anger or excitement.
"He let out a demented scream when he realized he had lost everything."