The Justice Department reported yesterday that about 16 percent of inmates in state prisons and local jails are mentally ill.

The report, the first comprehensive survey of its kind, said that mentally ill inmates were slightly more likely to have committed violent crimes than other inmates and much more likely to have been physically or sexually abused before their incarceration. It also said that a higher percentage of female inmates than male inmates suffers from mental illness, with the highest rate of mental illness -- 40 percent -- among white female state prisoners under 25.

Other studies have shown that prison inmates are more likely than other Americans to be the products of dysfunctional families with prior drug and alcohol problems and physical and sexual abuse. This survey, issued by the Bureau of Justice Statistics and based on a 1997 survey of prison and jail inmates, suggests that such a history is even more common among mentally ill prison inmates.

For example, an earlier Justice Department report said that among the general state prison population, 19 percent reported being abused before their incarceration, including 16 percent of male inmates and 57 percent of female inmates. The report released yesterday said that 37 percent of mentally ill prison inmates reported being abused, including 33 percent of men and 78 percent of women.

"The mentally ill are at least twice as likely to have been abused than other inmates," said Allen Beck, chief of corrections statistics for the Bureau of Justice Statistics. "What really comes through here consistently is that the mentally ill are far more likely to come from homes that are troubled, either with parents who have been incarcerated or abused alcohol or drugs. What is cause and what is effect is hard to sort out, but there is a consistent set of negative indicators -- alcohol dependence, drug use, life experiences. It's a package of really co-occurring problems."

In the survey, the Justice Department classified inmates as mentally ill if they said they currently suffered from a mental or emotional condition or if they reported an overnight stay in a mental hospital or other treatment facility. Paula M. Ditton, the Justice Department statistician who compiled the report, said that because of the methodology used, it was impossible to compare the survey's findings with statistics on mental illness among the general population.

But she said other research has shown that the mental illness rate among local jail inmates is about twice that of the general population. Ditton also said that the higher rate of mental illness among female inmates was consistent with the general population, largely because of depression.

In contrast to the 16 percent of state prison and local jail inmates who were estimated to be mentally ill, the report said that only slightly more than 7 percent of federal prisoners suffered from such conditions. Ditton said this reflected the nature of the federal prison population, which includes a significantly higher percentage of drug offenders than state prisons or local jails. For reasons Ditton said she could not explain, mentally ill inmates were less likely to have been convicted of drug offenses than other inmates.

According to the report, 53 percent of mentally ill state prison inmates had been convicted of violent crimes, compared with 46 percent of other inmates. This included 13 percent who had been convicted of murder. In federal prisons, 33 percent of mentally ill inmates had been convicted of violent crimes, compared with 13 percent of other inmates.

The report estimated that the mentally ill number 283,800 in the nation's prisons and jails. Almost a quarter of state prison inmates said their father or mother had served time in prison or jail, and 42 percent said a brother or sister had been incarcerated. The study also found that mentally ill state prison inmates were more than twice as likely as other inmates to have been homeless at some point during the year before their arrest and presented more discipline problems for prison authorities than other inmates.

Inmates and Mental Illness

Mentally ill inmates were more likely than other inmates to be in state prisons for a violent offense.

Violent

Mentally ill inmates 53%

Other inmates 46%

Property

Mentally ill inmates 24%

Other inmates 22%

Drug

Mentally ill inmates 13%

Other inmates 22%

Public order

Mentally ill inmates 10%

Other inmates 10%

SOURCE: Bureau of Justice Statistics