Defining the severely mentally disabled

Evaluation andprogram Planning, Vol. I, pp. 219-227, 1984 Printed

DEFINING

0149-7189/84 $3.00 + .OO 0 1985 Pergamon Press Ltd

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in the USA. All rights reserved.

THE SEVERELY

MENTALLY

DISABLED

WILLIAM A. HARGREAVES, MARIJEAN LEGOULLON, JESSICA GAYNOR, C. CLIFFORD ATTKISSON, and BABETTE BLOCH University

of California,

San Francisco

ABSTRACT A definition of the “known target population of severely mentally disabled” in community mental health centers is examined. Criteria include intensive treatment contact and persistent, severe disability, but not diagnosis. Feasible and reliable screening procedures are demonstrated. In the identified population, most subjects at some time had received a diagnosis of schizophrenia and had been on public assistance. These criteria apply to catchmented treatment systems and should be useful in services research.

quent encounters

In order to study the process and effects of a treatment system, the target group for which the system is responsible must be clearly definable. wish to test various interventions

Therefore, if we with the severely

mentally disabled or chronically mentally ill, we need a workable consensus on the definition of that popula-

this population

in any catchment

and (c) the person is “severely mentally disabled.” The definition refers only to information that is available in the records of most treatment systems. This definition differs from one that would be used for the study of incidence and prevalence, where restriction to those “known” to the treatment system would be undesirable. In the sections that follow, tion for proposing the specific

area.

In addition to the value of a clear definition when testing the effectiveness of interventions, program planners and administrators need such a definition if they are to monitor whether their programs are serving this population.

health system

the treatment system; (b) the person is a resident of the catchment area for which the system is responsible;

tion before trying to accumulate generalizable information about it. The definition must be one that can be applied consistently from one catchment area to another in order to conduct comparative research on networks of community services for the severely mentally disabled. Such a definition would consist of inclusion and exclusion criteria and would specify practical ways to identify

with the public mental

or the police. We suggest the appropriate target group is what we call the “known target population of the severely mentally disabled.” This group is defined by three features: (a) the identified person is “known” to

we discuss our motivaform of each part of the

definition. The key concepts are public mental health system, being known to the system, being the responsibility of the system,

They also need it if they wish to exam-

and being severely

mentally

dis-

abled.

ine the effects of policy changes such as tightened eligibility for public assistance. When treatment systems are catchmented, the special notion of responsibility for a target group is added - a sense in which the system is to be accountable for the outcomes of a group of people who themselves may be reluctant to persist in treatment. As a practical matter as well as a matter of individual freedom and privacy, treatment systems are not expected to search out those chronic mentally ill who do not have fre-

What is a “Public Mental Health System?” We define the public mental health treatment system of a catchment area as those mental health care activities that are funded by federal, state, and local government, excluding those provided under veterans’ benefits. Included in the system is the community mental health center (CMHC) or its counterpart, if one exists. The center may directly provide or may contract for inpatient care, various less restrictive or less medically

This work was supported by grant MH-34743 from the National Institute of Mental Health. Requests for reprints should be sent to William A. Hargreaves, Psychiatry Program Evaluation, San Francisco, CA 94103. 219

Room

7M3,

1001 Potrero

Avenue,

220

WILLIAM A. HARGREAVES et al.

oriented types of 24-hour treatment, day treatment or partial hospitalization, outpatient treatment, and various other services. State hospital care is considered a part of the system in the sense that any admission to the state hospital from an address in the catchment area or discharge to an address in the catchment area is defined as occurring within the system. Also, any continuing care, case management, or placement services operated by the state hospital are considered part of the system to the extent that they serve residents of the catchment area. Excluded from the system are the activities of VA facilities, private psychiatric and other medical care providers, private nursing homes and supervised residences, welfare and social service agencies, law enforcement agencies, and penal institutions, except insofar as any of these has a contract with the public mental health system to care for the severely mentally disabled target population. Participants may not view such a system as a definable entity, but this definition allows us to examine whether more explicitly recognized and coordinated systems are more effective or efficient than uncoordinated systems. Who is “Known to the System?”

A person is “known” only if some written record exists that would enable a professional in the system to recognize the person as being severely mentally disabled. We also require that there be a “qualifying contact,” or a treatment during the study period that was more intensive than outpatient care. Restricting the qualifying contact to intensive treatment provides a way to identify a high-risk sample, and makes screening more practical. For whom is the System “Responsible?”

A person must have a continuing residence in the catchment area to be unambiguously the responsibility of the public mental health system. However, potential ambiguities arise regarding persons placed in residential care in another catchment area, transients and

“street persons,” and persons who primarily use VA mental health services. While the boundaries of responsibility are not entirely clarified by drawing lines on a map, the proposed criteria include most people who ordinarily are defined as the responsibility of a catchmented public mental health system. Who is “Severely

Mentally

Disabled?”

Diagnosis, chronicity, and functional disability have all been used, separately or in combination, to define the severely mentally disordered (Goldman, Regier, Taube, Redick, & Bass, 1980; Goldman, Gattozzi, & Taube, 1981). Routine clinical diagnosis of schizophrenia has been criticized repeatedly for its unreliability (e.g., Spitzer & Fleiss, 1974). Neither does any one diagnosis define the chronically ill or the severely disabled, who are a subset within several diagnostic groups. In a survey of admissions to a sample of Community Mental Health Centers (Abt Associates, 1982), criteria depending primarily on diagnosis plus prior inpatient care showed little agreement with criteria based primarily on disability. Yet some diagnostic issues are relevant because programs for the “severely mentally disabled” are not designed for all types of serious psychiatric disorder. Distinct approaches exist for alcoholics, heroin and barbiturate addicts, the mentally retarded, and those with organic brain syndromes: Therefore, it seems wise to exclude persons whose disability results primarily from one of these conditions, leaving a group largely consisting of persons with schizophrenia, an affective disorder, or a severe personality disorder. The four concepts just mentioned are embodied in our proposed criteria. The concept of severe mental disability is extended from a set of criteria used for a time in the National Institute of Mental Health Community Support Program (Turner & Shifren, 1979). In this paper, we describe the implementation of screening procedures in two catchment areas, examine interrater agreement, describe the characteristics of patient groups included and excluded, and identify the key discriminating criteria.

METHODS Definition

of the Target Population

To be known to the public mental health system (CMHC) as severely mentally disabled (SMD), the subject must: have a qualifying contact, not be excluded, meet at least ONE of the primary SMD criteria at the time of a qualifying contact, and meet at least TWO of the secondary criteria for a 2-year period either just prior to a qualifying contact or at some later time during the study period in this catchment area.

Qualifying Contact. A qualifying contact is an instance within the dates of the study period when a subject was at least 18 years old but not yet age 66, and had any one of the following psychiatric contacts:

l l l

l

psychiatric day treatment, psychiatric inpatient care, discharge from a state hospital to an address in the catchment area, or psychiatric residentia1 treatment (including a halfway house or L-facility, but not simply living in a supervised residence).

The Severely Mentally Disabled Any of the preceding types of care must be provided by the CMHC in this catchment area, or by its related state hospital, or be provided elsewhere while the subject was a resident of the catchment area. Persons whose care is provided primarily by the VA are excluded. In addition, the subject must be known to be living in the catchment area during at least 1 of the 24 months following a month in which a qualifying contact occurred. Persons with an “all points” or no specific address may be considered residents if the treatment system seems to accept responsibility for them as if they were residents. Exclusions. People whose disability results primarily from mental retardation, alcoholism, drug abuse, organic mental disorder, or nonpsychiatric medical conditions are excluded. However, mental retardation, alcoholism, drug abuse, or organic mental disorder may be present if the subject was given a primary diagnosis of some other mental disorder, or if the abstractor judges that these exclusion disorders were not the primary cause of disability. Primary Criteria. The person must meet one of the following two criteria. 1. Treatment level. Present if subject has undergone psychiatric treatment more intensive than outpatient care more than once in a lifetime. Includes state hospital, other inpatient, “crisis bed,” and day treatment, but not emergency room or crisis service when not held overnight. A change in the level of care such as inpatient to day treatment is treated as a new episode. However, if after a discharge from hospitalization or from a crisis bed, subject is admitted again within 7 days, this is not considered a separate episode. 2. Supportive residence. Present if subject has experienced a single episode of continuous, structured supportive residential care other than hospitalization, for a duration of at least 2 months. Supportive residential care includes a residential care facility (“board and care home”), halfway house, psychiatric nursing home, or locked residential care (“L-facility”). It does not include living with family or friends, no matter how “supportive” they are, nor in a “cooperative apartment” program. Secondary Criteria. The person must meet two of the next five criteria. 1. Poor work history. Present if, on a continuing or intermittent basis for at least 2 years, subject was unemployed, employed in a sheltered setting, or had markedly limited skills and a poor work history. 2. Public assistance. Present if, on a continuing or intermittent basis for at least 2 years, subject required public financial assistance for out-of-hospital maintenance. The subject need not have actually received public assistance (e.g., if continuously in a state hospital), and may in fact be unable to procure such assistance

221

without help. This also includes subjects receiving private insurance funds for a mental disability. 3. Poor social support maintenance. Present if, on a continuing or intermittent basis for at least 2 years, subject showed severe inability to establish or maintain a personal social support system. A personal social support system consists of family or friends (outside of treatment facilities) who can be called upon by the subject for emotional or financial support, shelter, or other assistance in times of need. As a rule of thumb, subject may be considered to be maintaining a social support system if there is someone to pick up the subject from the crisis clinic, even if that person may provide the subject a place to stay for no more than a day or two. 4. Poor basic living skills. Present if, on a continuing or intermittent basis for at least 2 years, subject required help in basic living skills. Subject may not have received such help, but could not deal with such basic tasks as managing money, shopping, transportation, food preparation, or personal care. 5. Untolerated behavior. Present if, on a continuing or intermittent basis for at least 2 years, subject exhibited inappropriate social behavior that resulted in demand for intervention by the mental health and/or judicial system. Involuntary hospital admissions, arrests with booking, or petitioning for conservatorship or commitment must have occurred at least three times within 2 years or have resulted in restriction of the subject’s freedom (e.g., through the establishment of a conservatorship) for at least 3 months during the period. Sampling and Screening Sampling and screening was undertaken in two catchmented public mental health systems in northern California, which will be called CMHC A and CMHC B. The sampling was an attempt to assure that the cases were representative of the two treatment systems because cases identified as SMD were more extensively abstracted as part of a larger project. CMHC A is one of several catchmented mental health programs in an urban county. It serves a largely residential area of about 200,000 population. Sampling was facilitated by availability of a computer-based management information system (Attkisson & Nguyen, 1980) that provided a file of 19,000 unduplicated cases known to CMHC A. A study period was chosen from October 1975 (at the inception of the computer-based system) through March 1981. CMHC B is responsible for an entire suburban and rural county, also with a population of about 200,000. No computerized management information system was available, but central records with a master card file of about 30,000 unduplicated cases included persons seen since the late 1960s. Therefore, a longer study period was defined in CMHC B, from January 1971 through April 1982.

222

WILLIAM A. HARGREAVES et al.

Primary Screen. In each CMHC a subfile of cases was assembled, consisting of all patients who had at least one recorded episode of inpatient, partial, or halfway house care, and who were within ages 18 to 65 at some time during the study period. Sample blocks were randomly selected for screening, and sampling continued until secondary and tertiary screening had identified about 300 SMD cases in each CMHC. Secondary Screen. As we gained experience with the screening, we developed an additional set of secondary screening criteria: (a) eliminate patients who had only one inpatient contact and either no other contacts or only additional outpatient or emergency room contact; (b) eliminate cases with a total elapsed time of less than 6 months from first entry to last exit. Of all cases passing primary screening in CMHC A, 63% were eliminated by the secondary criteria. We tested the sensitivity and specificity of this secondary screen using 305 cases that would have been eliminated in the secondary screen but on whom tertiary screening was completed anyway, plus 482 that passed secondary screening. Of these 787 cases, 250 were identified as SMD cases. The secondary screen passed 234 of these 250 “true” SMD cases for a screening sensitivity of .94, while 289 of 537 “true” non-SMD cases failed the secondary screen for a specificity of .54. In CMHC B only 30% of the cases identified in the primary screen were eliminated by the secondary crite-

ria. An initial set of 97 cases failing secondary screening was again passed to tertiary screening, and were compared to 122 cases that passed the secondary screen. Of this total of 219 cases, 54 were identified as SMD cases. The secondary screen passed 50 of these 54 “true” SMD cases for a screening sensitivity of .93, while 93 of 160 “true” non-SMD cases failed the secondary screen for a specificity of .58, values very similar to those found in CMHC A. Tertiary Screen. Only at this stage did the abstracters need to read the narrative medical record, the most time-consuming aspect of sample acquisition. Experienced abstracters can complete the tertiary screen in 50 minutes per case, on the average. The inexpensive secondary screen provides an enriched sample at the cost of only a small loss of true SMD cases. Instead of examining the medical record of all cases that pass the primary screen, abstracters need only to examine the cases that pass the secondary screen. Because the secondary screen excluded fewer of the primary-screen qualifiers in CMHC B, the secondary screen “enriched” the tertiary screening sample only from 30% SMD in those passing primary screen to 41% SMD among those passing secondary screen, whereas in CMHC A a 20% SMD sample was enriched to 50% SMD. In spite of these differences, the secondary screening operated with very similar sensitivity and specificity in both systems.

RESULTS

Estimated Size of the Known Target Population of SMD Prevalence estimates depend on estimating each way in which true SMD cases were lost in our screening and sampling process. Table 1 shows the detailed screening outcomes in both CMHCs. The number of cases that passed through each screen or were finally identified as SMD are shown, along with interval estimates for the number of missed SMD cases (Fleiss, 1981, p. 14). In CMHC A this estimation took into account a further sampling stratification not presented here. In CMHC A, we estimate that had we carried out tertiary screening on all 2,058 cases that passed the primary screen, we would have identified an additional 79 to 251 persons as members of the “known target population of severely mentally disabled.” With 286 found, we therefore estimate that the total unduplicated count of known SMD during the 65-month study period was between 365 and 537. The 1980 population of Catchment Area A was 196,350, so the estimated 65-month prevalence is 187 to 275 per 100,000 population. Similarly, in CMHC B we have so far identified 226 SMD cases and estimate that were we to complete screening on all 1,335 cases passing primary screening,

TABLE 1 SAMPLING AND SCREENING PROCESS, NUMBER OF IDENTIFIED CASES, AND ESTIMATE OF TOTAL SIZE OF “KNOWN TARGET POPULATION OF SEVERELY MENTALLY DISABLED” IN TWO CATCHMENT AREAS Sampling

Subgroup

Passed primary screen Passed secondary screen Entered tertiary screen Qualified SMD Record lost Screening terminated Estimated missed SMD (95% Confidence interval) Failed secondary screen Entered tertiary screen Qualified SMD Screening terminated Estimated missed SMD (95% Confidence interval) Total qualified SMD Total estimated missed SMD Estimated population SMD (95% Confidence interval) Note. CMHC

= Community

Mental

CMHC A

CMHC

2,058 762 547 268 69 146 85 61-114 1296 305 18 991 43 18-137 286 128 414 365-537

1,335 886 609 222 8 269 101 74-128 449 97 4 352 15 O-60 226 116 342 300-414

Health

Center.

B

The Severely Mentally Disabled we would identify an additional 74 to 188 SMD cases, for a total SMD population of 300 to 414. Because the catchment area had a 1980 population of 222,568, this corresponds to a 136-month prevalence of 135 to 186 per 100,000 population. The different study period lengths make it hard to compare prevalence in the two catchment areas. A more useful figure for planning and research would be the l-month prevalence of the known target population for each of the months throughout each study period. These estimates require a definition of exit from the high-risk target population even though a person is still a resident of the catchment area, and attention to several possible sampling artifacts. The issues are fairly complex and will be presented in another paper. Demographic Characteristics of the Sample For 852 CMHC A cases and 615 CMHC B cases that have been examined at the tertiary screen, Table 2 shows the demographic characteristics of those identified as SMD and identified as not SMD (who nevertheless met primary screening criteria through inpatient, residential, or day treatment contact during the study period). In both catchment areas, younger persons and males tend to be more prevalent among the SMD. In CMHC A, the SMD population had completed slightly less education (as of 2 years before the first qualifying contact), although this trend was less prominent in CMHC B. The greater prevalence of males and of younger persons are related. This is consistent with the fact that the age at first treatment is lower for males than for females, among patients diagnosed as schizophrenic (Gottesman & Shields, 1982). Subject frequencies by

TABLE

223

age (in 1978) of the SMD and non-SMD men and women in CMI-IC A are shown in Figure 1. The frequency of all the groups tends to decline with age, but this is most striking among the men. Among the SMD, both sexes show relatively few cases after age 40, but there are relatively more young SMD men. The nonSMD groups of both sexes are prominent in the younger age groups, but the non-SMD women show a continuing prevalence following age 40. Corresponding plots for CMHC B (not shown) reveal similar contrasts between SMD and non-SMD groups, but with a smaller proportion of older persons in all groups than were seen in CMHC A. The differences between SMD and non-SMD groups are probably related to diagnosis. We will see later in this paper that the majority of SMD subjects have schizophrenia as their usual primary diagnosis. We did not examine diagnosis in the non-SMD group, but anecdotally we observed that most patients with affective disorders did not meet our stringent SMD criteria for a continuous 2-year period of severe disability. It may be that the greater prevalence of affective disorder in women (e.g., Slater & Cowie, 1971) accounts for the continued prominence of the non-SMD women in the older age groups. The younger SMD women, on the other hand, may be less likely to become estranged from their natural support systems, may be less likely to be seen as dangerous, and be more likely to be compliant with treatment. It may also be that these two treatment systems differentially recruit or export particular subgroups. This finding suggests that we need to be alert for possible interactions among age, gender, and SMD status in their relationships with other subject and service system characteristics.

2

CHARACTERISTICS OF SMD AND NON-SMD CASES THAT REACHED TERTIARY SCREENING IN TWO CATCHMENT AREAS CMHC A

Characteristic

SMD

Nor-&MD

Sample size Mean age in 1978 Percent male Mean years of education Ethnic percentages White Black Hispanic Asian Other Percent immigrants Percent English second lang.

266 36.2 63 11.2

566 37.9 37 12.5

66 14 6 13 1 16 10

66 13 5 13 2 19 14

CMHC B P’

.08 .Ol .Ol .07

.03 .06

SMD

Non-SMD

221 30.7 62 12.0

394 35.0 47 12.3

95 4 1 0 0 5 4

95 2 2 1 1 7 3

Note. CMHC = Community Mental Health Center; SMD = severely mentally disabled. lp vatues are based on t tests for scaled variables and uncorrected XI for categorical variables.

P’ .Ol .Ol .08 .41

.54 .93

224

WILLIAM

A. HARGREAVES

et al

TABLE 3 INTERRATER AGREEMENT IN MAKING THE SMD CLASSIFICATION AND IN CODING EACH COMPONENT CRITERION IN SAMPLES OF 52 CMHC A CASES AND 40 CMHC B CASES Percentage

SMD

25-

item

CMHC A

CMHC B

92 83 83 83 79 77

90 83 90 85 93

a6

90 85 100

SMD Classification Treatment level Supportive residence Poor work history Public assistance Poor social support maintenance Poor basic living skills Untolerated behavior Exclusions

F,’

Note. SMD = severely mentally nity Mental Health Center.

Non-SMD

Age

Group

Figure 1. Age Distribution of Men and Women in Severely Mentally Disabled (SMD) and Non-SMD Samples in Community Mental Health Center (CMHC) A.

Reliability of SMD Classification Two abstracters independently did the tertiary screening of 52 cases in CMHC A and 40 cases in CMHC B. Reliability cases were selected by oversampling those that the. initial abstractor had qualified as SMD, so that in each catchment area about half of the reliability cases were SMD cases. The overall agreement on the SMD classification was 92% and 90% in CMHC A and B respectively, which is excellent. Table 3 shows that agreement on individual items varied from 77% to 100%. The higher reliabilities in CMHC B may reflect the clarification of some ambiguities in the items. These clarifications are all reflected in the version of the screening criteria contained in this paper. In partic-

85 96 disabled;

CMHC

88

= Commu-

ular, improvement in rating “poor social support maintenance” reflects a narrowing of that concept. Public assistance seems to be more reliably documented in CMHC B than in CMHC A, which led to less disagreement . Characteristics of the SMD Target Group Table 4 shows additional information that was collected on 286 CMHC A and 221 CMHC B SMD subjects, beyond the demographic information in Table 2. The data in Table 4 are characteristics of the subjects only for that portion of their lifetime up to 2 years before their first “qualifying contact” in the study period. Considering that all the subjects had subsequent intensive treatment, and that these characteristics are probably underreported in clinical records, it is clear that this is a very disabled group. The two catchment areas show some interesting differences. The CMHC B SMD group shows more favorable prognostic characteristics in having more high school graduates, fewer with very low Global Assessment Scale (GAS) scores, fewer previous hospital admissions and less hospital time. On the other hand, the CMHC A group shows more favorable prognostic signs in the lower rate of suicidality, police involvement, and jail or probation. Finally, the CMHC B group was more likely to experience early treatment with antidepressants or lithium and not with depot neuroleptics, and shows a slightly lower proportion of subjects whose most common primary diagnosis was schizophrenia or who ever received neuroleptic medication. It is unclear whether these differences reflect different historical trends in the placement of state hospital patients in these communities during the early years of deinstitutionalization, or differences in more recent practices

The Severely Mentally Disabled

225

TABLE 4 CHARACTERISTICS OF THE “KNOWN TARGET POPULATION OF SEVERELY MENTALLY DISABLED” UP TO 2 YEARS BEFORE QUALIFYING CONTACT IN TWO CATCHMENT AREAS Catchment Characteristic

CMHC A

Sample size range High school graduates Highest GAS score less than 61 a Lowest GAS score less than 21 b Median hospital admissions No previous hospital admissions More than four hospital admissions Lifetime hospital time 5 1 month Lifetime hospital time > 6 months Lifetime hospital time > 2 years Suicide threat, gesture, or attempt Suicide attempt Aggressive behaviorc Police involvement Involuntary hospitalization Jail or probation Most common primary diagnosis schizophrenia Ever neuroleptic medication Ever depot neuroleptic Ever antidepressant Ever lithium

218 to 283 70 % 34 % 53% 2 22% 21 % 34 % 42 % 24 % 35% 18% 42% 37% 24% 19% 86 % 74% 27% 14% 4%

Area CMHC

B

68 to 216 78% 34 % 14% 1 44 % 13% 59% 20% 5% 55% 24 % 53 % 59 % 29 % 38 % 69 % 65 % 15% 33 % 15%

Note. CMHC = Community Mental Health Center. aGAS = Global Assessment Scale, Scored 1 to 100, where 91-100 is superior social functioning, l-10 implies need for constant supervision (Endicott, Spitzer, Fleiss, & Cohen, 1976). A score of 51-60 implies “moderate symptoms or general Functioning with some difficulty (e.g., few friends and flat effect, depressed mood and pathological self-doubt, euphoric mood and pressure of speech, moderately severe antisocial behavior). bA GAS score of 11-20 implies “needs some supervision to prevent hurting self or others or to maintain minimal personal hygiene (e.g., repeated suicide attempts, frequently violent, manic excitement, smears feces), OR gross impairment in communication (e.g., largely incoherent or mute). c”Aggressive Behavior” includes angry or threatening behavior but no physical attack, physical attack or destructive behavior, and arrest or hospital admission associated with violence or threats, and the highest reported level is the one recorded.

that tend to retain patients with certain characteristics in active treatment. Discriminating

Power of Component

Criteria

Although the primary and secondary SMD criteria form a consistent and plausible construct of the severely mentally disabled, they may not all be needed to adequately identify members of the target population. We examined the sensitivity and specificity of each screening criterion in predicting the SMD classification based on the full set of criteria. The results, shown in Table 5, are quite similar in the two sites. No one of the criteria has perfect agree-

ment with the overall classification. The primary criterion of “treatment level” has essentially perfect sensitivity in both catchment areas, but with poor specificity (33% and 23%). Thus, this variable finds all of the true SMDs but cannot rule out non-SMDs. The opposite is true for “basic living skills,” with perfect specificity but low sensitivity (19% and 10%). This variable can rule out non-SMD cases, but will miss many true SMD cases. The best overall screening criterion is “public assistance,” with 91% and 87% overall agreement, attained because it has both good sensitivity (detecting 85% and 73% of the true SMD cases) and high specificity (ruling out 94% and 97% of true non-SMD cases).

WILLIAM

A. HARGREAVES

et al.

TABLE5 RELATIONSHIPS OF COMPONENT ITEMS TO SMD CLASSIFICATION AMONG 852 CMHC A AND 615 CMHC B CASES THAT REACHED TERTIARY SCREENING Percent Agreement Item Treatment level Supportive residence Poor work history Public assistance Poor social support maintenance Poor basic living skills Untolerated behavior Note. CMHC = Community

Sensitivity

Specificity

A

B

A

B

A

B

60 76 87 91 71 67 58

52 75 81 87 62 64 75

100 61 97 85 34 19 32

99 71 96 73 7 IO 56

33 87 80 94 97 100 95

23 78 71 97 99 99 88

Mental Health Center.

DISCUSSIDN We have shown that it is feasible to screen and to define reliably the “known target population of severely mentally disabled” from case records, using criteria of previous intensive treatment and severe, persistent disability. We found in two different catchment areas that this SMD population also is predominantly schizophrenic and consists predominantly of Supplemental Security Income (SSI) public assistance recipients. We demonstrated that secondary screening criteria based only on the history of treatment contacts allow us to “enrich” the prescreened sample of cases, improving screening efficiency while losing relatively few true SMD cases. To supplement the criteria for severe mental disability, we have added a new aspect that defines the SMD individual’s relationship to the treatment system under study- the criteria that define the “known target population” of the system. Definitions of “residence” and “qualifying contact” are the key concepts. For longitudinal studies of system function and change, one must construct a definition of the target population that retains a similar meaning from the beginning to the end of a study period. The use of repeated qualifying contacts that “expire” after a time is one way to maintain a constant longitudinal definition of a target population. How can this definition aid studies that will be useful in mental health systems? One use is in estimating the prevalence of known SMD persons. Although the two CMHCs reported here had a relatively similar prevalence of known SMD persons, we have reason to think that other catchment areas may differ from this level by a factor of two or three, either higher or lower. We suspect that such differences will be underestimated from the relative caseloads in, say, day treatment. A definition that can be applied across different catch-

ment areas is necessary if one is to specify differences in case mix and accurately allocate treatment funds intended specifically for the severely mentally disabled. A second use of this definition is in treatment studies focused on the severely mentally disabled. In a multisite randomized experiment where alternative treatments are to be compared within each site, the definition would help to insure that investigators in all sites recruit subjects who have a comparable degree of severe mental disability. In a nonexperimental comparison of existing treatment “packages” in different sites, the definition would help to insure that subjects with comparable characteristics are examined in each treatment program. It would also reveal a difference in case mix from program to program, which itself may be an influential though unintended aspect of program design that can confound a nonexperimental comparison. In longitudinal quasi-experiments, the definition would be especially important. A change in policy (e.g., tightened eligibility for public assistance, or less stringent criteria for inpatient admission) may alter program effectiveness while simultaneously encouraging the migration of the severely mentally disabled either into or out of the catchment area. The two concurrent effects will be confounded unless a consistent definition of the target population allows one to detect migratory trends. It seems to us that services research has been impeded by confused definitions of the target population to be served. In the work reported here, we have demonstrated a feasible and reliable definition of the known target population of the severely mentally disabled. We suggest that it can provide a solid foundation for research on services to this population in any set of catchmented mental health systems.

227

The Severely Mentally Disabled

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