When John Hinckley Jr. was found not guilty by reason of insanity in the 1981 assassination attempt of President Ronald Reagan, jurors left open the possibility that he would one day live outside a mental institution. For decades he's been receiving treatment at St. Elizabeths Hospital in Washington, D.C., and in 2003 a judge ordered Hinckley be allowed to start testing his freedom outside of the facility. For the past year, Hinckley has spent 17 days a month living with his mother in Williamsburg, Virginia. Hearings set for Wednesday will determine whether that time should be increased. Nearing 60, Hinckley could potentially be granted full-time, year-round "convalescent leave" in the community.

Some questions and answers about Hinckley and the insanity defense:

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HOW OFTEN ARE DEFENDANTS FOUND NOT GUILTY BY REASON OF INSANITY RELEASED BACK INTO THE COMMUNITY?

Most people found not guilty by reason of insanity and confined to a psychiatric facility ultimately get to leave, though some do not, said Paul Appelbaum, a Columbia University psychiatry professor and past president of the American Psychiatric Association. A person's length of stay at a psychiatric hospital tends to be proportionate to their crime, Appelbaum said, and different states have different rules about how much control officials have once a person is released.

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HOW DID INSANITY DEFENSE LAWS CHANGE AFTER THE HINCKLEY CASE?

The jury's decision in Hinckley's case caused a public outcry. Congress and many states changed laws to make it more difficult for a defendant to win a case using the insanity defense. The use of the defense is rare. One commonly cited study of eight states published in the 1990s found insanity defense pleas used in about 1 percent of all felony cases, with only a quarter of those who used the defense being acquitted.

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WHO IS MONITORING HINCKLEY WHILE HE'S IN WILLIAMSBURG?

The Secret Service tails Hinckley intermittently when he's outside of St. Elizabeths, and in the past he's had to provide detailed itineraries of where he will be and when. When he's at his mother's house, she or his siblings supervise him. He and his mother also have to have daily telephone contact with the hospital.

Hinckley also has weekly one-on-one visits with his psychiatrist and a therapist while in Williamsburg and has to attend a weekly group therapy session, according to a court order. During his latest Williamsburg visits, he's also supposed to be seeing a music therapist. And he has to carry a GPS-enabled cellphone so his location can be tracked.

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WHAT IS THE LIKELIHOOD HINCKLEY WILL EVER BE 100 PERCENT FREE?

The judge overseeing Hinckley's case has been quoted as saying he expects to have the Hinckley case as part of his docket until he dies, or Hinckley does, suggesting ongoing oversight even if Hinckley is allowed to go on "convalescent leave," living outside the hospital full time. A prior plan suggested that even if Hinckley is allowed to remain in Williamsburg, he would have to return regularly to St. Elizabeths for outpatient visits.

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WHAT ABOUT OTHER PROMINENT DEFENDANTS FOUND NOT GUILTY BY REASON OF INSANITY?

In 1993, Lorena Bobbitt severed her sleeping husband's penis. She testified she had endured years of beatings, rapes and emotional abuse, and a jury found her not guilty by reason of insanity. After five weeks in a state mental hospital, Bobbitt was released after the hospital and judge agreed she was not a danger to herself or others. The court ordered her to continue therapy, then lifted that order in 1996.

Texas mother Andrea Yates was initially convicted of drowning her five children in a bathtub and sentenced to life in prison, but during a 2006 retrial a jury found her not guilty by reason of insanity and she was sent to a mental hospital. In 2012, a judge declined to let her attend church services outside the hospital. In 2014, she and her doctors asked that she be allowed to leave the institution for group outings with other patients, but the request came under such scrutiny it was withdrawn.