A prisoner (also known as a prisoner or detainee) is a person deprived of liberty because of his or her will. This can be achieved by limiting, imprisoning, or imposing constraints. The term is particularly applicable to serving a sentence in prison. The term does not apply to pre-trial defendants.

"Prisoner" is the legal term for a prisoner.

In Section 1 of the prison Security Act 1992, the term "prisoner" refers to a person who is currently in prison and is detained as a result of any requirement imposed by the court or otherwise.

"Prisoner" is the legal term for a person charged with a felony. It does not apply to a person charged with a misdemeanor. Article 1 of the 1967 criminal law abolished the distinction between felony and misdemeanor, making the distinction obsolete.

Glanville Williams described the term "prisoner" as an "unbelievable" practice of not convicting people

Among the most extreme adverse effects on prisoners, it appears to be the result of prolonged solitary confinement. When prisoners are held in "special housing units" (Shus), they suffer from sensory deprivation and lack of social interaction, which may have a serious negative impact on their mental health.

Taking it for a long time may lead to depression and physiological changes in the brain. In the absence of the social environment needed to verify their understanding of the environment, prisoners become resilient, extremely sensitive, and more vulnerable to the vulnerability of those who control the environment. The support provided by social relations and social interaction is the premise of long-term social adaptation of prisoners.

After long-term solitary confinement, prisoners show the paradox effect of social withdrawal. There has been a shift from the desire to expand social connections to fear. They may become drowsy and apathetic, and when released from solitary confinement, they will no longer be able to control their actions. They can rely on prison structures to control and limit their actions.

Long term living alone can lead to the development of clinical depression and long-term impulse control disorder. People with mental illness have a higher risk of psychiatric symptoms. Some common behaviors are self mutilation, suicidal tendencies and psychosis.

A psychopathological condition identified as "Shu syndrome" has been observed in these prisoners. Symptoms are characterized by attention and memory, perceptual distortion, and hallucinations. Most of the criminals with Shu syndrome show extreme generalized anxiety and panic, and some suffer from amnesia