INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, VOL. 7: 83-87 (1992)

PSYCHIATRIC DIAGNOSES MADE BY THE AGECAT SYSTEM IN RESIDENTS OF LOCAL

AUTHORITY HOMES FOR THE ELDERLY: OUTCOME AND DIAGNOSTIC STABILITY

AFTER FOUR YEARS DAVID AMES

Senior Lecturer in Psychiatry of Old Age, University of Melbourne Department of Psychiatry, Clinical Sciences Building, Royal Melbourne Hospital, Parkville, Victoria, 3050, Australia

SUMMARY Eighty-six residents of 12 local authority homes for the elderly were interviewed with the Geriatric Mental State (GMS) in 1985/6 after having been classed as depressed by a screening interview. The data so gathered were analysed by the computerized diagnostic program AGECAT in order to derive psychiatric diagnoses for these residents. All were traced after four years; 61 were dead. The 25 survivors were reinterviewed and given a second AGECAT diagnosis. In 1985/6 70 of the 86 examined were ‘diagnostic cases’ of psychiatric disorder. After four years 22 of the 25 survivors were classed as diagnostic cases. AGECAT diagnoses of organic psychosis were stable over four years within this population though the majority of subjects so diagnosed died within four years. Cases of depression had a more varied prognosis, with death, continuance as cases of depression or progression to organic psychosis being the most common outcomes. Recovery from any class of AGECAT disorder was an uncom- mon event.

KEY woms-Survey, AGECAT, residential care, diagnosis

Because epidemiological studies of psychiatric dis- order among elderly subjects require a consistent and reliable diagnostic method (Copeland et al., 1 988), Copeland and co-workers have developed a computerized diagnostic system (AGECAT) (Copeland et al., 1986) which utilizes data derived from a semistructured interview, the Geriatric Mental State (GMS) (Copeland et al., 1976), to make diagnoses of the commoner psychiatric syn- dromes encountered among the elderly. In its first stage, the AGECAT program groups symptom components into eight diagnostic clusters and allo- cates each subject a level of confidence between 0 and 5 for each cluster. Subjects with confidence levels of 3 and above for any given cluster are referred to as ‘syndrome cases’, while those with confidence levels of 1 and 2 are ‘subcases’. Depend- ing upon the symptoms present, it is possible for a subject to be classed as a syndrome case or sub- case on none, any or all of the eight clusters in stage 1. In its second stage, AGECAT compares these diagnostic clusters with one another and uses

hierarchical rules to allocate each subject one main diagnosis where appropriate. Subjects are referred to as ‘diagnostic cases’ of particular disorders (organic, schizophrenic, manic or depressive psy- choses, depressive, hypochondriacal, obsessional, phobic or anxiety neuroses) when the confidence level of the main diagnosis is at level 3 or above, and again those with confidence levels of 1 and 2 are subcases of disorder. Research to date indi- cates satisfactory reliability for the system, and good concordance between diagnoses made by AGECAT and those made by individual psychia- trists (Copeland et al., 1988).

Although the concurrent validity of AGECAT has been assessed, less is known about the predic- tive validity of the system or the long-term pro- gnoses of subjects who are classed as diagnostic cases. If diagnostic cases of organic psychosis represent cases of dementia, one would expect these diagnoses to remain stable over years in those indi- viduals who survive. A greater variety of outcomes might be expected for diagnostic cases of depressive

0885-6230/92/02008345$05.00 0 1992 by John Wiley & Sons, Ltd.

Received 23 April 1991 Accepted 2 July 1991

84 D. AMES

psychosis and neurosis, but given the results of pro- gnostic studies of depressed elderly (Ames and Allen, 1991), one might surmise that a considerable proportion would remain cases of depression over several years. Both organic and depressed diagnos- tic cases might be expected to have raised death rates in comparison to well subjects, and a three- year follow-up of a community sample indicated that this was indeed the case, with organic cases having an odds ratio for mortality 4.39 times that of the well group, while the comparable odds ratio for cases of depression was 1.74 (Davidson et al., 1988).

To date no published study has presented data on subjects who were allocated AGECAT diag- noses on two separate occasions, several years apart. The current investigation was undertaken in order to establish outcomes and diagnostic stabi- lity after four years for 86 subjects who had been allocated an AGECAT diagnosis after interview with the GMS during a study of depression in 12 local authority homes for the elderly (Ames, 1990).

METHOD

In 1985/6,390 of the 439 residents of the 12 homes for the elderly run by Camden Council were screened for cognitive impairment and depression. Details of this work have been published elsewhere (Ames et al., 1988; Ames, 1990). Ninety-three resi- dents (1 7 males, median age 82 years) met inclusion criteria for a more detailed study of the types of depression detected and the efficacy of psychiatric intervention for depressive symptoms. These cri- teria required residents to score 7 or more on the 24-point depression scale (DEP) of the Brief Assess- ment Scale (BAS) (MacDonald et al., 1982; Mann et al., 1989). This score had been determined as the optimum cutpoint for a psychiatrist’s identifica- tion of individuals suffering from a ‘significantly depressed state’ (Mann et al., 1984). In order to exclude those with severe dementia whose affective state would be impossible to assess, the DEP was not administered to 112 subjects who received the maximum score of 8 on the Organic Brain Syn- drome scale (OBS) of the BAS. Nevertheless, the group of 93 residents with scores of 7 or more on the DEP did include several subjects with signifi- cant cognitive impairments. The current author then examined 86 of these 93 residents with the GMS (four refused and three died before GMS interview). Prior to these interviews the author was

trained in the use of the GMS by experienced raters. Ten of the interviews were co-rated with another experienced interviewer, and a satisfactory level of interrater reliability was attained (Ames, 1990). For the current study all 86 residents who had under- gone GMS interview in 1985/6 were traced in July 1990, and the author reinterviewed all the survi- vors, again using the GMS. Thus the reinterviews were not conducted blind, though the author did not have the 1985/6 diagnoses before him at the time of reinterview. The new GMS data were ana- lysed by the AGECAT program to yield stage 1 and 2 AGECAT diagnoses as had been done in 198516. The two sets of diagnoses made over four years apart were then compared, in order to cast light on the stability and predictive validity of the AGECAT system in this population.

RESULTS

Residents traced and assessments performed The follow-up interviews took place over one week in July 1990, between 48 and 59 months after the initial GMS interviews (median 54 months). Twenty-five of the 86 subjects were still alive. All survivors were interviewed. Eight had moved from their original residential home to another Camden Council home (six because of home closures), one was in a long-stay dementia ward at a psychiatric hospital, and one was in a voluntary sector home.

Deaths and stability of AGECAT diagnoses after four years The fate of the 86 residents and the diagnoses of the survivors are tabulated against their initial AGECAT diagnosis in Table 1.

The interview with the subject who was a subcase of organic disorder (02) in both 1985/6 and 1990 was limited by her severe deafness on both occasions.

The subject rated as a case of schizophrenia in 1986 and as a case of depressive psychosis in 1990 was free of delusions and hallucinations at her second interview and was taking haloperidol. The subject whose diagnosis changed from depressive psychosis to schizophrenia had developed mood- incongruent delusions during the follow-up period.

At follow-up, four depressive neurosis cases and three depressive psychosis cases had become diag- nostic cases of disorders other than depression.

PSYCHIATRIC DIAGNOSES BY AGECAT 85

Table 1. Initial AGECAT diagnoses for 86 residents of local authority homes for the elderly compared to their AGECAT diagnoses four years later

AGECAT diagnoses 1990 AGECAT diagnoses 198516 Dead 0 5 0 4 0 3 0 2 s3 S1 DP4 DN4 DN3 D1 Total

0 5 13 13 0 4 5 1 1 7 0 3 5 3 8 0 2 5 1 6 01 1 1 s5 1 1 s2 1 1 DP5 1 1 DP4 5 1 6 DP3 4 1 1 1 1 1 9 DN4 1 1 2 DN3 14 3 1 1 1 2 1 23 D2 3 1 4 D1 2 2 AN2 2 2 Total 61 2 5 5 1 1 1 5 1 3 1 86

0, organic psychosis; S, schizophrenic psychosis; DP, depressive psychosis; DN, depressive neurosis; D, depression (subcase level); AN, anxiety neurosis. Numbers indicate confidence levels for diagnoses. Confidence levels 3-5 represent ‘diagnostic cases’, levels 1-2 represent ‘subcases’ of disorder.

However, all seven still had depressive symptoms. In 1990 five were classed as syndrome cases of depression in stage 1 of AGECAT in addition to being syndrome cases of organic or schizophrenic psychosis. The latter diagnoses took precedence in stage 2 because they have higher status in the AGE- CAT hierarchy. The other two residents whose diagnoses changed from depression at follow- upwere now subcases of depression (D2) in stage 1.

DISCUSSION

A cohort of residents from homes for the elderly, who were defined as depressed in a screening inter- view and allocated diagnoses by the AGECAT sys- tem, were traced after four years and all survivors were allocated a second AGECAT diagnosis. The special nature of the initial sample (depressed inmates of residential homes for the elderly), the small number of survivors, the absence of an ‘AGE- CAT well’ comparison group, and the lack of a blind follow-up assessment imply that the results of this study should be interpreted with caution. Nevertheless, the study yields unique information

on the stability of AGECAT diagnoses over a four- year period.

Death rates were high, as has been the case in earlier research on residential home populations (Booth et al., 1983; Ashby et al., 1991). The small numbers in the individual diagnostic categories pre- vent meaningful statistical comparison between categories, but it is of interest that the highest death rate (82%) occurred in subjects with an initial diag- nosis of organic psychosis, as was the case in the three-year follow-up of the Liverpool community sample (Davidson et al., 1988), and that among the diagnostic cases of organic psychosis death rates were highest for those with the highest diag- nostic confidence levels.

The follow-up AGECAT diagnoses indicated impressive diagnostic stability for the organic psy- chosis cases diagnosed in 198516. As predicted, these subjects either died or remained cases of organic psychosis. Four of the five survivors showed a rise in the confidence level of their diagno- sis, consistent with the progressive cognitive impairment seen in most dementing individuals, and the fifth subject showed no improvement.

The cases of depressive psychosis and neurosis had a greater variety of outcomes and recovered less frequently than might have been anticipated

86 D. AMES

at the study outset. Overall, the prognosis for AGE- CAT depressions was very poor with 59%” dying over four years, 15% dementing, 20% remaining diagnostic cases of depression, 2% developing schi- zophrenia, 5% becoming subcases of disorder and none showing complete recovery. Follow-up studies of subjects with AGECAT depressions detected in other settings, such as the community or acute psychiatric units, ought to show better outcomes than those found in this chronically dis- abled and environmentally deprived cohort (God- love et al., 1982). Eight of the 17 survivors with an initial diagnosis of depression had been placed in residential care after hospital inpatient treatment for depression. Often this placement had been dir- ectly related to failure to recover sufficiently to per- mit a return to independent living, further biasing the sample towards chronicity. The frequent pas- sage of subjects from one category of depression to the other may have been due to the fact that the psychosis and neurosis categories seem to define levels of severity rather than two clearly differen- tiated clinical syndromes. Of course, the endoge- nous/neurotic controversy is one of the enduring themes of postwar psychiatric research (Aspin, 1990; Andrews and Neilson, 1990), but this follow- up suggests that the subclassifications of depression built into the AGECAT program may have limited utility. Seven of 20 non-demented residents devel- oped organic psychoses over the follow-up period, and six of these came from the group of 17 who were diagnostic cases of depression in 1985/6, a higher number than would be expected on the basis of earlier work on the prognosis of depression in the elderly (eg Murphy, 1983). From a clinical view- point, the conclusion of the author was that the seven new cases of organic psychosis represented one case of multi-infarct dementia (she had suffered a recent stroke) and six of probable or possible Alzheimer’s disease. This finding may reflect the special nature of the depressed population of these homes, many of whom suffered from multiple physical illnesses (Mann et al., 1984) and whose ages were higher than those of most subjects taking part in other prognostic studies of late-life depression (the ages of these seven subjects at follow-up ranged from 81 to 87). Depressed individuals from these homes showed evidence of cerebral atrophy on CT scan when compared to normal controls (Ames et al., 1990), perhaps indicating that the majority came from the poor prognosis group with cerebral ventricular enlargement defined by Jacoby et al. (1981) and that, for some, their depressive symp-

toms were the first manifestation of a dementing process.

Only three of the 25 survivors were mere subcases of disorder in 1990, and none was rated as ‘well’ by AGECAT, indicating that the initial depression screen had been successful in defining a population with a high level of persistent chronic psychiatric disorder.

The AGECAT system is an important develop- ment in psychiatric epidemiology, and a satisfac- tory performance in the diagnosis of the common syndromes of dementia and depression is essential to its future. This small study suggests that within a population from residential homes, diagnoses of organic psychosis are predictive of either death or progressive cognitive impairment, while subjects with diagnoses of depression seem to have a more varied outcome, though few recover. Because of the small size of the sample and the high attrition rate, bigger studies will be needed in order to con- firm the poor prognostic implications of a diagnosis of organic psychosis and to further elucidate the outcome of diagnostic cases of depression. The high death rate found among these elderly subjects after four years indicates that future investigators study- ing AGECAT outcomes should select samples more representative of the age range of the total elderly population and reinterview their subjects earlier, probably on a yearly basis over at least three years. This methodology has been adopted in an outcome study of AGECAT depressions now underway in Melbourne. The assessment of out- comes of the six AGECAT disorders other than depression and organic psychosis will require larger samples of elderly subjects selected from the com- munity or enrolled at specialist treatment facilities.

ACKNOWLEDGMENTS

From 1985-1987 when the initial data were col- lected, Dr Ames’ salary was paid by a grant from the National Unit for Psychiatric Research and Development. The reexaminations of 1990 were made possible by a travel grant from the University of Melbourne. Thanks for assistance are due to John Copeland, Mike Dewey, Eleanor Flynn, Irene Goldstone, Nori Graham, Angela Hawkins, Yvonne Liddicoat, Anthony Mann, Camden Council social services staff and the residents who participated in the research. Deborah Ashby, Leon Flicker, George Patton, Pauline Ruth and two ano-

PSYCHIATRIC DIAGNOSES BY AGECAT 87

nymous referees made helpful comments on drafts of the manuscript.

REFERENCES

Ames, D. (1990) Depression among elderly residents of local authority residential homes: Its nature and the efficacy of intervention. Brit. J. Psychiat. 156,667-675.

Ames, D. and Allen, N. (1991) The prognosis of depression in old age: Good, bad or indifferent? Znt. J . Geriatv. Psychiat. 6,47748 1.

Ames, D., Ashby, D., Mann, A. H. and Graham, N. (1988) Psychiatric illness in elderly residents of Part III homes in one London borough: Prognosis and review. Age Ageing 17, 149-256.

Ames, D., Dolan, R. and Mann, A. (1990) The distinc- tion between depression and dementia in the very old. Znt. J. Geriatr. Psychiat. 5 , 193-198.

Andrews, G. and Neilson, M. (1990) Personality and outcome of depression. Brit. J . Psychiat. 157,929-930.

Ashby, D., Ames, D., West, C., MacDonald, A. J. D., Graham, N. and Mann, A. H. (1991) Psychiatric mor- bidity as a predictor of mortality for residents of local authority homes for the elderly. Int. J. Geriatr. Psy- chiat. 6, 567--575.

Aspin, A. J. (1990) Personality and outcome of depression. Brit. J. Psychiat. 157,929.

Booth, T., Phillips, D., Barrit, A,, Berry, S., Martin, D. and Melotte, C. (1983) Patterns of mortality in homes for the elderly. Age Ageing 12, 240-244.

Copeland, J. R. M., Dewey, M. E. and Griffiths-Jones, H. M. (1986) Computerised psychiatric diagnostic sys- tem and case nomenclature for elderly subjects: GMS and AGECAT. Psychol. Med. 16,89%99.

Copeland, J. R. M., Dewey, M. E., Henderson, A. S.

et a/. (1988) The Geriatric Mental State (GMS) used in the community: Replication studies of the compu- terised diagnosis AGECAT. Psychol. Med. 18, 219- 226.

Copeland, J. R. M., Kelleher, M. J., Kellett, J. M. et al. (1976) A semi-structured interview for the assess- ment of diagnosis and mental state in the elderly. The Geriatric Mental State Schedule. 1. Development and reliability. Psychol. Med. 6,439449.

Davidson, I . , Dewey, M. and Copeland, J. (1988) The relationship between mortality and mental disorder: Evidence from the Liverpool longitudinal study. Znt. J . Geriatr. Psychiat. 3, 95-98.

Godlove, C., Richard, L. and Rodwell, G. (1982) Time for Action: An Observation Study of Elderly People in Four Different Care Environments. University of Sheffield, Sheffield.

Jacoby, R., Levy, R. and Bird, J. (1981) Computed tomo- graphy and outcome of affective disorder: A follow-up study of elderly patients. Brit. J. Psychiat. 139, 288- 292.

MacDonald, A., Mann, A., Jenkins, R., Richard, L., Godlove, C. and Rodwell, G. (1982) An attempt to determine the impact of four types of care upon the elderly in London by the study of matched groups. Psychol. Med. 12, 193-200.

Mann, A,, Ames, D., Graham, N. et 01. (1989) The relia- bility of the brief assessment schedule. Int. J. Geriatr. Psychiat. 4,221-225.

Mann, A., Graham, N. and Ashby, D. (1984) Psychiatric illness in residential homes for the elderly: A survey in one London borough. Age Ageing 13,257-265.

Murphy, E. (1983) The prognosis of depression in old age. Brit. J. Psychiat. 142, 11 1-1 19.