FOUR PRISONERS WHO HAD BARRICADED THEMSELVES INSIDE THE TELEVISION ROOM OF THE CANADIAN PENITENTIARY SERVICE'S WESTERN REGIONAL MEDICAL CENTER WERE ISOLATED IN THIS STUDY. EACH CELL WAS APPROXIMATELY 80 SQUARE FEET IN AREA AND HAD A SMALL WINDOW. THE TWO RINGLEADERS WERE IN PADDED CELLS FOR A MONTH WITH THE ONLY FURNISHED ITEM BEING A TOILET. THE OTHER TWO, WHO WERE ISOLATED FOR A WEEK, HAD A FOAM RUBBER MATTRESS AND WERE ESCORTED TO THE TOILET WHEN NECESSARY. EACH INMATE RECEIVED THREE MEALS A DAY AND WAS ALLOWED 1 HOUR OF EXERCISE ALONE; OTHER PRIVILEGES WERE NONEXISTENT. ONE RINGLEADER, WHO SERVED THE FULL 30 DAYS OF ISOLATION, BECAME AT ONE POINT AGITATED BUT AFTER BANGING ON THE DOORS, GRADUALLY CALMED DOWN. BY THE THIRD WEEK HE EXPRESSED POSITIVE INTEREST IN MAKING SOCIALLY DESIRABLE CHANGES. AFTER HIS DISCHARGE FROM THE CENTER HE WAS FOUND TO BE PLEASANT, OPTIMISTIC, AND SELF-CONFIDENT, AND HE SPENT HIS LONGEST PERIOD OUTSIDE OF PRISON SINCE HE FIRST GOT INTO TROUBLE. THE SECOND INMATE CHANGED BY CEASING TO BOAST AND FANTASIZE ABOUT HIS PHYSICAL PROWESS, BY OBEYING ALL INSTRUCTIONS, AND BY BECOMING MORE COOPERATIVE. HOWEVER, AFTER HE WAS FREED, HE WAS REARRESTED TWICE FOR BREAKING AND ENTERING; HIS BEHAVIOR DURING THE SUBSEQUENT CONFINEMENT HAS BEEN ACCEPTABLE. ALTHOUGH THE THIRD INMATE CONTINUED TO BE MOODY AFTER ISOLATION, HE DID BECOME MORE COOPERATIVE AND MORE WILLING TO PARTICIPATE IN THERAPY, WHILE LIVING UP TO THE CONDITIONS OF HIS PAROLE. THE FOURTH BECAME QUIET, RELAXED, AND HE SLEPT WELL WITHOUT MEDICATION. HE RETURNED TO HIS FAMILY WHEN RELEASED. HE HAS NOT RETURNED TO ANY MENTAL HOSPITAL OR PRISON. ALL FOUR RECEIVED GRADUAL COMMUNICATION FROM NURSES WHILE IN ISOLATION. THE STUDY CONCLUDED THAT ISOLATION AND ENVIRONMENTAL MONOTONY, COUPLED WITH A SERIES OF RELIEF PRODUCING EVENTS, APPEARED TO HAVE GOOD SHORT-TERM EFFECTS ON THESE FOUR PEOPLE. REFERENCES ARE INCLUDED. (JLF)