Israel is one of the few countries in the world to maintain a nationwide record of every psychiatric hospitalization in a psychiatric case register (1). This paper discusses the potential uses of this database, which have not been fully exploited. We will also compare the situation in Israel with that in other areas of the world where similar registers are maintained.

The Israeli psychiatric case register, maintained since 1950, was enacted into law in the Treatment of Mentally Ill Act of 1955 and reaffirmed in the updated 1991 version of the law. Institutions with psychiatric admissions are required to file a report of each admission with the Ministry of Health. Since 1950 the names of about 130,000 patients have been entered into the psychiatric case register. About 93,000 of those patients are still alive. Approximately 16,000 hospitalizations are recorded annually, including some 4,000 first-time admissions whose names are added to the register.

As with most nationwide registers (2), the Israeli psychiatric case register covers primarily inpatient services, including information pertaining to the hospitalizations of adults and children in psychiatric hospitals and in psychiatric departments of general hospitals. Overall, 34 institutions are required by law to report information to the psychiatric case register. Ambulatory visits in any setting are not included, although day hospitalizations are.

Israel's psychiatric case register, which covers a population of close to six million, is perhaps the world's largest. The only other nations that maintain a nationwide psychiatric case register are Denmark, with a population 5.3 million (3), and New Zealand, with a population of 3.6 million (4). Norway, with a population of 8 million, founded a psychiatric case register in 1916 (5). However, it was abolished in 1988 because of public concerns about confidentiality (3).

The special advantage of a nationwide psychiatric case register is that it can eliminate the confounding effect of migration on the calculation of changes in an area's rates of hospitalization over time (6,7). For example, areas with a declining population may be expected over time to have an increasingly destitute population with a higher rate of long-stay inpatients, although this rate may actually be the artifact of the contracting general population. A nationwide register can avoid this pitfall.

A shortcoming of nationwide registers is that they are essentially limited to inpatient services. The possibility of maintaining records of a wider range of services on such a broad scale without compromising the reliability of the information has usually proven too daunting a task (2). In Israel, a record of patient contacts at government psychiatric outpatient clinics is also maintained and has been computerized in recent years (8), but this information is not centrally pooled, for reasons of maintaining confidentiality. On the other hand, many other countries maintain regional psychiatric case registers that cover both inpatient and various outpatient services, providing a fuller picture of a patient's treatment history as he or she moves through both the hospital and the community. Eight such registers exist in England alone, in areas with populations varying from 100,000 to 500,000 (9). Twelve other European countries (10), as well as parts of the United States (11) and Australia (12), maintain regional psychiatric case registers.

In Israel as elsewhere, the data included in the standardized report of hospitalization submitted by the admitting institution has been altered over the years to reflect changes in psychiatric practices. For example, data from day hospitalization units were first included in the register in 1980. The box above summarizes the types of data currently included in the Israeli register. A total of 26 data fields are currently included, which is similar to the number of fields in most psychiatric case registers (13).

Accuracy of the demographic data is enhanced by comparing the information submitted by the hospital about the patient with the data available through the population files of the Ministry of the Interior. The psychiatric case register is also regularly updated to include data on patients' deaths, even when they occur many years after the last discharge.

Although the types of data collected by different psychiatric case registers vary, they all include data on psychiatric diagnoses based on one of the various classification systems (14). Since 1997 the Israeli psychiatric case register has used the ICD-10 for diagnostic classification. The diagnosis is assigned clinically, usually by the admitting physician, and may be altered at discharge by the treating psychiatrist. The diagnoses are rarely determined by structured interview.

A study undertaken to determine the reliability of these diagnoses found that nearly 60 percent of diagnoses recorded in the psychiatric case register did not change over time (15). Among those that did change, 90 percent of the changes took place during the first admission and not subsequently.

Research elsewhere on reliability of case register diagnoses has been mixed. In Ireland a comparison of diagnoses in the psychiatric case register with those derived from an interview using the Present State Examination showed a high concordance (16). A World Health Organization collaborative study in the United Kingdom showed an 85 percent concordance between psychiatric case register and ICD-9 diagnoses (17). A Danish study suggested that the diagnosis of schizophrenia is more likely to be given after the first admission (3). A subsequent comparative investigation showed that patients were more likely to be diagnosed as having schizophrenia during their first admission in Mannheim, Germany, than in Denmark (18). One may conclude that despite advances in the reliability of recorded diagnoses, it remains a potential weak spot in psychiatric case registers (19).

The extensive data contained in the psychiatric case register can be exploited for four often-overlapping purposes: development of public health care policy, quality control, epidemiological and services research, and notification of other agencies.

Public health care policy

A psychiatric case register can aid in planning, implementing, and assessing public health care policy. The value of case register data for this purpose has been demonstrated in many localities. To choose one well-documented example, register information was vital to the development of community services in Salford, England (20). The Salford psychiatric case register, which monitored all contacts with a comprehensive range of services, helped determine the populations in more dire need of services, such as elderly persons. Ambulatory services were expanded, resulting in many more treatment contacts, as corroborated by the register. Some of the subsequent findings of analyses using the register were quite unexpected, such as the inability of a huge increase in the availability of community services to reduce the use of inpatient services.

Psychiatric case registers that—unlike the Salford example—cover only hospital care may nevertheless be invaluable for developing policy because they provide data on chronic inpatients, the frequency of the revolving-door phenomenon, or new long-stay patients (13).

In Israel, the psychiatric case register has helped guide public mental health policy, as the following three examples show.

The chronic inpatient population.

Chronic patients, defined as those with one year or more of consecutive hospitalization, numbered 4,610 at the end of 1996. They accounted for 69.3 percent of all psychiatric hospital beds, a rate of .8 beds per 1,000 persons in the general population. Old age, single marital status, previous hospitalizations, and a diagnosis of schizophrenia predicted a chronic stay at admission (21).

The rate of .8 chronic beds per 1,000 population is higher than in other countries in the Western world. In various areas of the United Kingdom, for example, the rate ranges between .43 and .6 (22,23,24). Such findings provided the impetus for the further reduction of hospital beds and the concomitant development of community services in Israel (25,26).

The revolving-door patient. Although the phenomenon of the revolving-door patient has been variously defined, the term generally refers to the patient who is frequently admitted for psychiatric hospitalization. The emphasis on deinstitutionalization has brought with it the risk that many erstwhile chronically hospitalized patients, now treated in the community, will require frequent rehospitalizations. Using data from the psychiatric case register, a study of first admissions followed for three to nine years revealed that 13.6 percent were admitted four or more times (27). That rate was similar to findings of 11 percent at ten-year follow-up and 14.6 percent at five-year follow-up in studies using psychiatric case register data in Denmark (28) and New Zealand (4), respectively.

An internal audit of psychiatric case register data at Israel's Ministry of Health revealed that 14.7 percent of the 19,087 people who were hospitalized in the two-year period of 1996-1997 had been admitted at least three times, and 7.1 percent had been admitted four times or more. The group admitted at least three times included 2,801 persons who had accumulated an average of 186 days of inpatient use during those two years alone.

Based on this information derived from the psychiatric case register, the mental health services section of the Ministry of Health decided to institute a policy of case management targeting this revolving-door patient population. In this instance, the case register was used to define the cohort of patients who required special community care to prevent rehospitalization. Whether the case management program will prove effective is by no means a foregone conclusion (29), and, based on the data derived from the psychiatric case register, the ministry is instituting a research program aimed at evaluating the costs and benefits of the program. The psychiatric case register will enable the Ministry of Health to follow subsequent hospitalizations and thus to determine whether the case management initiative is bearing fruit.

Mental health care reform.

The information available through the psychiatric case register will permit an assessment of the mental health care reforms taking place in Israel. For example, psychiatric hospitalization is currently government financed. As an incentive to reducing the duration of hospital stays, a differential pay scale has been proposed, whereby hospitals receive greater per diem remuneration for briefer stays. The psychiatric case register will be a crucial tool both for debating the implementation of this policy and for evaluating its ramifications (30).

Quality control

Quality control has become an important tool for evaluating and improving the quality of care delivered at medical institutions (31). Various strategies may be adopted to assess the quality of care. The psychiatric case register can play an important role in the process. Two examples will demonstrate this point.

Outcome studies.

Quality assessment may take the form of outcome studies (32). For example, the Ministry of Health may set the goal that only 10 percent of discharged patients with schizophrenia are to be readmitted in the course of a year. If the ministry, using the psychiatric case register, were to identify a community or catchment area that significantly exceeded that goal, a closer study of the ambulatory services, housing accommodations, and the like in that area might be indicated.

Accounting for different outcomes.

Variation among different institutions in treatment and outcome is inevitable. Yet when the differences are marked, the reasons should be investigated, and if possible the institutions with the better outcomes should be studied so that their methods can be understood and possibly applied elsewhere (33). For example, according to the data from the psychiatric case register, 6.9 percent of all hospital admissions last 48 hours or less. However, while most hospitals do not deviate much from the mean, some do, and the variation ranges from 2 percent to 18.4 percent, a ninefold difference. What are the reasons? Do some hospitals admit patients who need not be admitted at all? Or do they succeed through more aggressive therapy or other means in reducing hospital stay? Or is their catchment-area population perhaps different to begin with? As in the example of the effectiveness of case management in limiting the revolving-door phenomenon, the psychiatric case register serves as an instrument for initially assessing a problem and subsequently defining a cohort to be evaluated.

Epidemiological and services research

The psychiatric case register has been used for epidemiological and services research. For example, an analysis of case register data revealed that hospitalized patients tended to come from locations that were more socioeconomically deprived (34). By scrutinizing these findings, investigators concluded that for these patients, reduced socioeconomic status was a result of disability rather than an environmental circumstance that precipitated the disease (35), a conclusion also noted in another study (13).

Israel's psychiatric case register has furthered the study of trends in the local utilization of hospital services. For example, studies have examined the characteristics of persons with chronic disorders who become new long-stay patients in hospitals despite advances in the availability of community care. Lerner and colleagues (36) used the case register to follow patients admitted during a calendar year. They concluded that 10 percent will continue to require intensive, long-term inpatient services. In another study, investigators who looked at first admissions over a ten-year period found that 14 percent became revolving-door patients (27). Risk factors for joining this group included not being married, unemployment, and more severe psychiatric diagnosis. Lerner (37) has summarized the results of other studies involving data from Israel's psychiatric case register.

In another study, substance abuse was examined using data for more than 50,000 discharges between 1989 and 1992 (38). Substance abuse comorbidity was reported for 13.2 percent of male inpatients and 3.6 percent of female inpatients. The diagnosis was most common for patients with a diagnosis of personality disorder.

Notification of other agencies

The Israeli psychiatric case register was developed in the 1950s in response to a perceived need to maintain a record of citizens undergoing psychiatric hospitalization. A case can be made that when the law requiring the case register was enacted, neither public policy nor epidemiology was foremost in the legislature's mind, but rather the perceived need to protect society from persons with mental illness (39).

The information contained in the psychiatric case register is sensitive, and only its authorization by the Treatment of the Mentally Ill Act of 1991 prevents it from constituting a possible violation of the Patient's Rights Act of 1996, which provides for the protection of patient confidentiality. Similarly, in certain well-defined situations, the law permits transferring the information contained in the psychiatric case register to other institutions for purposes of protecting public safety. Computerization has simplified the transfer of information, thereby requiring increased care to safeguard confidentiality (40). The cases in which information may be transferred are summarized below.

Armed forces recruitment.

A list of citizens meeting age requirements for armed forces recruitment who have been hospitalized with serious diagnoses is transferred to the Israel Defense Forces. These diagnoses include psychotic and affective disorders, most emotional disorders that have involved a suicide attempt, substance abuse, and disorders of impulse control. Information about persons involved in work requiring a high-level security clearance is also released to the relevant authorities. The goal and justification for transferring this information is to aid the armed forces in decisions of recruitment and training of these individuals.

License to carry firearms.

According to the Firearms Act of 1949, the Ministry of Health, using information contained in the psychiatric case register, may notify the firearms register of the Ministry of the Interior that an applicant to carry firearms has been hospitalized for psychiatric reasons. In such instances, the applicant will have to undergo a special examination before being allowed to carry arms.

A person carrying a license to bear arms who is hospitalized will similarly be examined at the time of license renewal. Reevaluation of a hospitalized person's clinical condition can be undertaken immediately if the person's mental health therapist notifies the Ministry of Health of possible danger, as mandated by the same law.

Motor vehicle operation.

The Transport Act of 1961 allows the Ministry of Health to notify the Institute for Road Safety that an individual has been hospitalized. In practice, such notification does not occur unless the individual's therapist informs the institute of the possible danger.

Psychiatric care.

Case register information is also used for psychiatric purposes. The municipal psychiatrist faced with a decision about a patient's involuntary hospitalization will receive a synopsis of prior hospitalizations and diagnoses. Similarly, a hospital may request such information about patients who are currently hospitalized. Occasionally, a hospital requests general statistical data about hospitalizations at that institution.

Research does not constitute a sufficient reason for release of data about specific people who have been hospitalized. The research that is conducted using case register data does not entail the release of any information that could compromise a patient's anonymity.

Despite the many uses to which the Israeli psychiatric case register has been put, certain problems remain. If they were rectified, the value of the case register would be enhanced.

First, the case register primarily includes data only on inpatient services. Several reasons exist for this limitation. For example, the register was established at a time when community services were not developed. In addition, at least part of its rationale included the need to prevent certain "undesirables" from serving in the security forces (39). Furthermore, because the register is nationwide, the collection of data from the full range of psychiatric services is a potentially overwhelming task (2).

It is time to reconsider the case register's limitation to services offered in inpatient settings. The government-operated community clinics have computerized databases (8). This huge body of information is not collected centrally, due to a well-founded sensitivity to the considerable risk of a breach in medical confidentiality. Nevertheless, separate local outpatient databases can be combined with the inpatient psychiatric case register to provide a more comprehensive picture of the mental health system, as has been done successfully elsewhere (19). Confidentiality can be protected if the information is transmitted to a central pool without including identifying data such as name and identification number. Recently devised computerized records from community-based vocational and residential settings could also be included. The need for a rational policy of deinstitutionalization demands that such information be made available.

A second problem is that the psychiatric case register has not been mined for its research potential. Studies about patients' mortality, fertility, and season of birth have not been carried out. A major advance in this area would entail linking the register with other databases. For example, in Norway and Denmark linkages between the psychiatric case register and the register of twins were used to evaluate the genetic contribution to schizophrenia by comparing concordance between monozygotic and dizygotic twins (5,13). Linking the Israeli psychiatric case register to other databases would similarly enlarge the amount of information to be culled for studies of season of birth, obstetrical complications, mortality patterns, and migration.

A third problem is that the psychiatric case register's potential for discerning trends in the inpatient population—such as the degree of chronicity, the characteristics of new chronic patients, and mortality patterns—has not been realized. Linkage to other databases would add to this potential. However, the psychiatric case register may be most valuable in defining research questions or identifying the cohort to be followed. The actual research must then be done in the field and not in front of the computer.

For example, as noted earlier, case register data was used to determine that mental illness—especially schizophrenia—led to reduced socioeconomic status, rather than being caused by it (34,35). To confirm these results, a field study involving interviews with 4,914 adults born in Israel was undertaken. The findings for schizophrenia were confirmed, yet findings for depression among women and substance abuse disorders among men suggested that social causation was more noteworthy (41).

Similarly the psychiatric case register should be exploited more often as a basis for further field studies, as in the two examples noted: a study of case management policy, intended to follow a cohort of revolving-door patients identified through the psychiatric case register, and a study of brief admissions, which vary greatly from hospital to hospital and must be assessed on site. If research strategies involving the register are carried out more frequently, more questions of policy, quality assurance, and research will be resolved.

A fourth concern is the need to add new types of data to the register. The types of information included are periodically reviewed and updated, and the demands of deinstitutionalization suggest the need to collect additional types of data. For example, is the patient being admitted from a hostel, a sheltered apartment, or his or her own home? Does the patient work in competitive employment, in a sheltered workshop, or not at all? Moreover, data on costs might help in assessing the economics of hospitalization, especially if the differential scale for remuneration of hospitals takes effect (42).

Israel's psychiatric case register is a powerful tool for developing and implementing policy, for conducting research, and for diagnosing and treating the problems of the psychiatric hospitalization system. However, its full potential is yet to be tapped. With further linkage with other sources of information and additional use in field studies, the psychiatric case register promises to provide the data necessary to operate mental health care delivery services more efficiently while advancing the cause of research about mental illness.

The authors dedicate this article to the memory of Miriam Popper (1939-1997), who for more than three decades was instrumental in developing and maintaining the Israeli psychiatric case register as a tool for planning and research.

All of the authors except Dr. Grinshpoon are affiliated with the mental health services section of the Israel Ministry of Health, P.O. Box 1176, Jerusalem 93461, Israel (e-mail, licht@cc.huji.ac.il). Dr. Lichtenberg is chief of hospital services, Dr. Kaplan is director, Ms. Feldman is director of the research, evaluation, and planning division, and Ms. Nahon is acting director of the department of information and evaluation. Dr. Grinshpoon, formerly head of the clinical services division in the mental health services department of the Israeli Ministry of Health, is currently assistant director of Sha'ar Menashe Psychiatric Hospital.