Mentally ill and mentally deficient (IQ of 70 or below) offenders pose a difficult set of challenges for the correctional worker. Schizophrenics probably account for more criminal offenses than all other mental patients combined. The most serious form is process schizophrenia, a condition that develops insidiously over a long period of time. These are individuals whose histories show an early inability to function normally, to make friends, to handle schoolwork, and to behave acceptably. The second type is reactive schizophrenia, where the individual may not have a history of psychological and social dysfunction but is subjected to an acutely stressful experience that creates the onset. Mental health professionals identify schizophrenia by these four symptoms: autism, ambivalence, inappropriate affect, and loose association. Schizophrenics have great difficulties in filtering information, and focusing their attention and responding appropriately to environmental stimuli. The schizophrenia syndrome is linked to brain structure and functioning, genetic predisposition, and strong environmental input. The job of the criminal justice worker is to act as a medication monitor for schizophrenics, and to put them in touch with various community agencies, such as sheltered workshops and specialized counseling services. High IQ tends to be relatively incompatible with crime (at least street-level crime), and the mentally deficient commit a disproportionate amount of crime. Most delinquents and criminals are in the normal (90-110) range of intelligence, and intellectually capable of profiting from counseling, education, and training. However, low IQ offenders present some special supervision difficulties. One of the major problems is helping them secure work in an increasingly technological society. Such offenders require special attention to self-esteem, self-consistency, and lots of patience. All instructions should be phrased as simply as possible to avoid misunderstanding. 55 references, 2 figures