Psychotropic drug use rate among detention house residents and association with the category of the crimes in Japan

Abstract Aim The White Paper on Crime 2019 from the Japanese Ministry of Justice reported that the percentage of crimes committed by people with mental disabilities was only 1.0%. In contrast, the findings of a statistical survey of correctional facilities reported that 15.1% of the prisoners were diagnosed with a mental illness. This study aimed at clarifying the relationship between mental illness and crime among suspects in a detention house and explaining this large gap. Methods Criminal suspects who were newly admitted in the Gifu detention house in Japan were eligible for the study. The status of psychotropic drug use was investigated, and its relationship with age, sex, offense history, and type of crime was analyzed. Newly prescribed medications in detention houses or police stations were excluded. Results In total, 26.5% of the residents in a detention house used psychotropic drugs. The psychotropic drug use rate was 16.7% (excluding the sleeping pill use rate). The use rates of sleeping pills, anxiolytics, antidepressants, and antipsychotics were 22.6%, 11.1%, 3.0%, and 9.6%, respectively. Psychotropic drug use was high in illicit drug users and low in suspects for immigration violence. Psychotropic drug use was higher among female suspects, suspects in their 40s and 50s, and suspects with a multiple crime history. Anxiolytic (17.0%) and antipsychotic (11.9%) use rates were high among suspects for violence. Conclusion In total, 26.5% of the subjects used psychotropic drugs. Psychotropic drug use was high in illicit drug users and low in suspects for immigration violence.


| INTRODUC TI ON
In Western countries, mental illnesses are related to all or some crime categories, such as arson and violence. [1][2][3][4][5][6][7][8] However, the White Paper on Crime, 2019, from the Japanese Ministry of Justice reported that the percentage of crimes committed by people with mental disabilities was only 1.0%. 9 The Cabinet Office of Japan reported that the percentage of people with mental illnesses nationwide was 3.3% 10 ; thus, it was concluded that people with mental illnesses were less likely to commit crimes than healthy people. In contrast, the Japanese Ministry of Justice published the findings of a statistical survey of correctional facilities, which reported that In other countries than Japan, some studies have reported the rate of mental illnesses among prisoners. Fazel et al 12 conducted a systematic review of mental disorders among prisoners in Western countries in 2001 and reported that 3%-7% of men had psychotic illnesses; of these, 10% had major depression and 65% had personality disorders, with 47% having antisocial personality disorders. They also reported that 4% of women had psychotic illnesses; of these, 12% had major depression and 42% had a personality disorder, with 21% having antisocial personality disorder. Seth et al 13 16 reported that 39.6% (46% men and 29.5% women) of the prisoners had a current psychiatric disorder. All the studies reported that the prevalence of mental illnesses in prisoners was much higher than that in the general population. The relationship between mental illness and crime could not be determined from these studies because the targeted subjects were already imprisoned. Thus, its influence on imprisonment or the court's judgment could not be avoided.
Although our original research question was "what percentage of criminals are considered to have a mental illness at the time of arrest?," we changed our research question to "what percentage of suspects in the detention house used psychotropic drugs at the time of arrest?" The reason we focused on psychotropic drug use was that it was extremely difficult to obtain diagnostic information from criminals or suspects in Japan. In contrast, we could easily obtain information of suspect's past psychotropic drug use in a detention house, which provided following benefit. In Japan, prisoners are sent to different types of prisons according to their crime and past history of the crime. Therefore, even if we obtained the data from several prisons in Japan, those data would not represent the general demographic of criminals. Detention houses admit all suspects in the region who committed the crime and are awaiting the court's final judgment, of whom 99% are usually charged guilty. Thus, the data of suspects in the detention house somehow represent the general demographics of criminals in Japan. Furthermore, we analyzed the relationship between psychotropic drug use and the crime category. To the best of our knowledge, no similar surveys have been conducted in Japan or other countries. This study may bring new perspectives on the relationship between crime and mental illness and a new strategy to decrease crimes committed by people with mental illness.

| Subjects
Criminal suspects who were newly admitted in the Gifu detention house in Japan from December 1, 2017, to November 30, 2019 were eligible for the study. The Gifu detention house is located in Gifu City, which is the capital of Gifu Prefecture. This is a typical middle-sized city in Japan. The medical staff of the detention house gathered the suspects' information, including sex, age, history of medication use, type of crime, and other information. We collected the data after anonymization. The status of psychotropic drug use was investigated and confirmed by referring to hospitals sometimes, and its relationship with age, sex, offense history, and type of crime was analyzed.
Newly prescribed medications in detention houses or police stations were excluded. Medications are free in the detention house.

| Categorization of crimes and psychotropic drugs
The crime categories included theft, illicit drug abuse, violence, traffic infringement, sex crime, embezzlement, arson, murder, immigration violation, and other crimes. For each suspect, only the name of the main offense was considered, including attempts. Therefore, if suspects were arrested for violence and possession of an illicit drug, they would be placed in the violence category.
We divided psychotropic drugs into the following six groups: anxiolytics, antidepressants, sleeping pills, antipsychotics, antiepileptics, and anti-manic drugs. Anxiolytics and sleeping pills were defined according to "Today's remedy 2020 in Japan." 17

| Statistical analyses
Statistical analyses were performed using JMP ® version 10.0.2 (SAS Institute). The background characteristics of each group and psychotropic drug use were compared using the chi-square test, and the odds ratios were calculated. To compare the different items of each category, the standard groups were the 20-29 group and theft group; theft was the most common crime in Japan.

| Ethical statement
This study was approved by the Ethical Review Committee of the Gifu University's Graduate School of Medicine on December 5, 2018December 5, (approval no: 2018. Data were collected as part of an obligatory investigation to obtain information from all suspects in the detention house but not for this study. For this reason, the opt-out method cannot be used in a detention house. Therefore, informed consent was waived. This point was discussed and approved by the Ethical Review Committee. We were given access to the data after anonymization.

| RE SULTS
The background characteristics of the suspects are shown in used all types except sleeping pills. The most used drugs were sleeping pills (22.6%). A total of 11.1%, 3.0%, 9.6%, 1.9%, and 0.4% of the suspects used anxiolytics, antidepressants, antipsychotics, antiepileptics, and anti-maniac drugs, respectively. Combined use of psychotropic drugs is depicted in Table 3. We found that the subjects who used antipsychotics had a tendency to combine them with other psychotropic drugs.
The relationship between psychotropic drug use and the crime categories is shown in Table 4. A high percentage of psychotropic drug use (38.9%) was observed among suspects for illicit drug abuse.
For subjects who committed arson, this percentage was extremely high. Among suspects for violence, anxiolytics (17.0%) and antipsychotics (11.9%) were the most used. Psychotropic drug use among suspects for immigration violence (6.8%) was extremely lower than that among suspects for other crimes.
The relationship between psychotropic drug use and crime category was investigated again, considering theft as a standard crime.
The results are presented in Table 5. The findings were consistent with those outlined in Table 4. Suspects for illicit drug abuse used psychotropic drugs more than suspects for theft. Moreover, the suspects for immigration violations used psychotropic drugs less than those for theft.
The relationship between psychotropic drug use and the suspects' background characteristics (eg, sex, age, and crime history) was investigated. The results are shown in Table 6. Psychotropic drug use was significantly higher among suspects in their 40s and 50s than among those in their 20s. Psychotropic drug use among female suspects was significantly higher than that among male suspects. We also found that suspects who had committed multiple crimes used psychotropic drugs more than those who had committed crimes only once.

| D ISCUSS I ON
This is the first survey to analyze the relationship between psychotropic drug use and crime categories in Japan and other countries. We found that 26.5% of suspects used psychotropic drugs.
When users of sleeping pills were excluded, the psychotropic drug use rate was 16.7%. Mishima et al 18 studied psychotropic drug use in the general population of Japan. According to their study, the use rates of sleeping pills, anxiolytics, antidepressants, and antipsychotics were 5.00%, 4.72%, 2.62%, and 0.89%, respectively.
The use rates of sleeping pills, anxiolytics, antidepressants, and antipsychotics were 22.6%, 11.1%, 3.0%, and 9.6%, respectively, in our survey. Therefore, the use rate of psychotropic drugs except antidepressants was much higher among suspects than in the general population.
We found that psychotropic drug use was significantly higher among suspects in their 40s and 50s than those in their 20s.
Psychotropic drug use increases with aging. However, the use rates in suspects in their 60s and 70s were not high. The reason for this is unknown. In addition, psychotropic drug use was higher among female than male suspects. Some studies reported that the prevalence of mental illnesses was higher in women than in men. 15 house but not for this study. For this reason, the opt-out method cannot be used in a detention house.

I N FO R M E D CO N S E NT
For the above reasons, informed consent was waived. This point was discussed and approved by the Ethical Review Committee. We were given access to the data after anonymization.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data that support the findings of this study are available on request from the corresponding author. The detention house which provided the data to us understood the value of our research and admitted only our research. Therefore, if someone wants to use the data, we will try to get an approval from the detention house. We hope your understanding of the particular position of the detention house.