The Nordic concept of reactive psychosis a multicenter reliability study Hansen H, Dahl AA, Bertelsen A, Birket-Smith M, von Knorring L, Ottosson J - 0 , Pakaslahti A, Retterstol N, Salvesen C, Thorsteinsson G, Vaisgnen E. The Nordic concept of reactive psychosis - a multicenter reliability study. Acta Psychiatr Scand 1992: 86: 55-59.
H. Hansen’, A. A. Dahl’, A. Bertelsen’, M. Birket-Smith3, L. von Knorring4, J.-0. Ottosson’, A. Pakaslahti‘, N. Retterstel’, C. Salvesen*, G. Thorstein~son~, E. Vaisanen l o
’
Department of Psychiatry, University of Oslo, Norway, * University Psychiatric Hospital, Arhus, Department of Psychiatry, Copenhagen Community Hospital, Glostrup, Denmark, Department of Psychiatry, University of Uppsala, Department of Psychiatry, University of Gothenburg, Sweden, Department of Psychiatry, University of Helsinki, Finland, Gaustad Hospital, University of Oslo, Sandviken Hospital, University of Bergen, Norway, Department of Psychiatry, University of Iceland, Reykjavik, Iceland, l o Department of Psychiatry, University of Oulo, Finland
’
I
Reactive psychosis is a common diagnosis in the Nordic countries (Norway, Sweden, Denmark, Finland and Iceland) and in several other parts of the world. In ICD-9 and DSM-111-R, the concept is defined more narrowly than in the Nordic tradition. In this study we examined the interrater reliability of the Nordic concept by the case-summary method between clinicians from 9 university departments in the Nordic countries. The results show that Nordic psychiatrists have a reasonably reliable concept of reactive psychosis, and that this psychosis can be diagnosed as reliably as schizophrenia and affective psychosis.
Reactive psychosis as a diagnostic category was described by German psychiatrists toward the end of the nineteenth century. In General psychopathology, Jaspers (1) separated “true reactions” from other functional psychoses. Reactive psychosis had a content that reflected the life event, and it would not manifest itself without the event. The course depended on the development and duration of the event. The concept was introduced to Scandinavian psychiatrists especially through the work of Wimmer in Denmark, which was presented at the first Nordic congress for psychiatrists in 1913. In his monograph, Wimmer (2) gave the following definition: By reactive psychoses we mean various clinically independent psychoses that are characterized as follows. They are caused by psychic traumas that hit a predisposed individual. These traumas are decisive for the onset of the psychosis, the course (remissionintermission-exacerbation) and the recovery. The psychosis in form and content more or less directly and completely reflects the triggering psychic trauma in an understandable way. To these criteria we can add that these disorders mostly have a favorable outcome, and especially that they do not lead to dementia.
Key words: reactive psychosis; schizophrenia; affective disorder; nosology Alv A. Dahl, MD, Department of Psychiatry, Oslo University, P.O. Box 85, Vinderen, N-03 19 Oslo, Norway Accepted for publication February 1, 1992
The first follow-up study of reactive psychosis was conducted by the Danish psychiatrist Fzrgeman (3) on a sample of 170 patients from Wimmer’s clinic in Copenhagen. At follow-up 16-19 years later, he was able to verify the diagnosis in 70 patients, about half of the cases with reactive psychosis. The other half had developed schizophrenia or manic-depressive psychosis over the years. This heterogeneity of the reactive psychoses at follow-up led Slater to reject the concept (4). Also, the word psychogenic, which is often connected to these psychoses, was criticized by Lewis (5). This explains why the concept of reactive psychosis did not catch on in the Englishspeaking countries. However, the concept had widespread use in Russia, Japan, German-speaking countries, France and the Nordic countries. This leads to the inclusion of reactive psychoses under other psychoses in ICD-8 (6), despite opposition from the representatives of the United Kingdom and the United States. ICD-9 (7) points to a narrow concept of reactive psychoses:
55
Hansen et al. Categories 298.0-298.8 should be restricted to the small group of psychotic conditions that are largely or entirely attributable to a recent life experience. They should not be used for the wider range of psychoses in which environmental factors play some (but not the major) part in aetiology.
The concept of reactive psychosis was made still narrower in DSM-111-R (8). A diagnosis of brief reactive psychosis requires the appearance of psychotic symptoms shortly after and apparently in response to events that would be markedly stressful to anyone, a duration of less than 1 month and full return to the premorbid level of functioning. As pointed out by Jauch & Carpenter (9), this defines a very restricted category. In the ICD-10 Clinical Diagnostic Guidelines (lo), acute and transient psychotic disorders, which include stress-related disorders, have a rather narrow definition. The first psychotic symptoms develop within 2 weeks of an event that would be regarded as stressful to most patients. Complete recovery usually occurs within 1 month. For the schizophrenia-like subtype, the duration has to be less than 1 month and for the delusional and polymorphic subtypes less than 3 months. Neither DSM-111-R nor ICD-10 includes the affective syndromes. These trends in international classification are in contrast to the broad concept of reactive psychoses used in the Nordic countries. However, even within the Nordic countries at least 4 concepts of “reactive psychosis” had been in use (1 1): 1) Reactive psychosis is a functional psychosis that is not clearly schizophrenic, manic-depressive or paranoid type (12). 2) Reactive psychosis is a purely psychogenic psychosis caused by a traumatic psychological situation (13). 3) Reactive psychosis is a functional psychosis with good outcome (14). 4) Reactive psychosis is characterized by an interaction of trauma and vulnerability (15). Should Nordic psychiatrists keep the tradition of reactive psychosis or join the international classification? To answer this, it is important to know how consistent and reliable Nordic psychiatrists are in using this diagnosis. This study, therefore, examines 3 relevant questions by use of the case-summary method: What is the interrater reliability of the diagnosis of reactive psychosis within and between the Nordic countries? Does the interrater reliability of reactive psychosis differ from that found for schizophrenia or affective psychosis? What is the interrater reliability of various functional psychoses in DSM-111-R compared with ICD-9 and national classifications?
Material and methods
Dahl and Hansen prepared 30 case histories of patients treated for functional psychosis at the Department of Psychiatry, University of Oslo. Dahl and Hansen and the clinicians who treated the patients diagnosed these cases independently according to ICD-9. Fifteen cases (base rate 0.50) had a diagnosis of 298.0-298.8 reactive psychosis ( 5 each of affective, confusional and paranoid subtype). Five cases had 295 schizophrenia, 5 296 affective psychosis and 5 295.7 schizoaffective schizophrenia (base rate 0.17 each) according to consensus of the clinicians and Dahl and Hansen. These diagnoses fulfill Spitzer’s LEAD standard (16), as they are based on longitudinal observation and expert clinicians who had all data, and they are considered as master ratings. The departments of psychiatry at 2 university hospitals in each country participated in the study, except for Iceland, which has only one university (Denmark: Arhus and Copenhagen; Sweden: Uppsala and Gothenburg; Norway: Oslo and Bergen; Finland: Oulo and Helsinki; and Iceland: Reykjavik). An experienced psychiatrist at each site diagnosed the 30 cases according to 3 classification systems: ICD-9, DSM-111-R and national tradition, the latter defined as the traditional diagnostic practice used for the various functional psychoses in each country. The psychiatrists were also asked to indicate their diagnostic confidence on each case on a 3-point scale. A score of 1 meant a certain, typical case, a score of 2 represented a probable case with minor uncertainty and a score of 3 meant that the case was uncertain and doubtful. Cohen’s kappa was used for the statistical analysis. The intercenter reliability was calculated by the formula for 2 raters and polychotomous data (17). Table 1. Sensitivity, specificity and number of the ICD-9 diagnosis of reactive psychosis and mean confidence ratings of the centers compared with the master rating
No. of cases Center
Oslo Bergen Arhus Copenhagen Uppsala Gothenburg Oulo Helsinki Reykjavik
Sensitivity
Specificity
0.53 0.53
1.00 1.00
0.47 0.93 0.47
1.00
of reactive psychosis
Mean confidence rating
8
12
1.83 1.50 1.75 1.34 1.44 1.41 1.18 1.74 1.53 1.52
8 7 26 7 10
0.73
0.20 0.87 0.93 0.93 1.00 0.93
Mean
0.56
0.87
10.1
Median
0.53
0.93
8
0.60 0.40 0.40
7 6
Reliability of reactive psychoses Table 2. Kappa values for interrater reliability between various centers Norway
Master Oslo Bergen Arhus Copenhagen Uppsala Gothenburg Helsinki Espoo
Denmark
Sweden
Finland
Iceland
Oslo
Bergen
Arhus
Copenhagen
Uppsala
Gothenburg
Helsinki
Espoo
Reykjavik
0.73
0.73 0.76
0.65 0.76 0.76
0.53 0.41 0.30 0.27
0.53 0.52 0.71 0.71 0.22
0.73 0.84 0.68 0.68 0.49 0.80
0.56 0.59 0.67 0.67 0.30 0.55 0.52
0.85 0.80 0.72 0.64 0.46 0.60 0.79 0.56
0.80 0.76 0.76 0.76 0.43 0.74 0.60 0.68 0.80
Since Iceland had only one site, Reykjavik was compared with the master ratings. A kappa value above 0.75 was considered as high interrater reliability, between 0.50 and 0.74 medium and below 0.50 low. Results
For ICD-9 compared with master ratings, the sensitivity for reactive psychosis was 0.50 and above at 5 sites (Table 1). The specificity was over 0.87 at all sites except Copenhagen, where it was only 0.20. The master rating diagnosed 15 cases of reactive psychosis. The rater in Copenhagen diagnosed 26 such cases; for the other sites the number varied between 6 and 12 (mean 10.1). The kappa values for the intercenter reliability of reactive and nonreactive psychosis varied between 0.23 and 0.84 between sites (Table 2). Thirteen of 45 ratings (29%) showed a kappa value of 0.75 or higher. Kappa values between 0.50 and 0.74 were found for 23 ratings (51 %); 9 ratings (20%) showed a kappa value below 0.50. However, all low intercenter reliability ratings were connected with the rater in Copenhagen. If Copenhagen is not included, 36% of the ratings had high and 64% medium intercenter reliability on the distinction between reactive and nonreactive psychosis. When percentage agreement among raters is applied, the agreement at or above 80% was higher for nonreactive than for reactive psychosis (P< 0.001). When reactive psychosis is compared with schizophrenia, schizoaffective psychosis and affective psychosis, the percentage agreement of reactive psychosis spread between the low agreement found in schizoaffective psychosis and the high agreement found in affective psychosis (Table 3). The raters were quite confident about the diagnosis of reactive psychosis, since the mean confidence rating for these cases was 1.47. This was lower than the mean (1.53) for nonreactive psychosis in ICD9 (P
H. Hansen’, A. A. Dahl’, A. Bertelsen’, M. Birket-Smith3, L. von Knorring4, J.-0. Ottosson’, A. Pakaslahti‘, N. Retterstel’, C. Salvesen*, G. Thorstein~son~, E. Vaisanen l o
’
Department of Psychiatry, University of Oslo, Norway, * University Psychiatric Hospital, Arhus, Department of Psychiatry, Copenhagen Community Hospital, Glostrup, Denmark, Department of Psychiatry, University of Uppsala, Department of Psychiatry, University of Gothenburg, Sweden, Department of Psychiatry, University of Helsinki, Finland, Gaustad Hospital, University of Oslo, Sandviken Hospital, University of Bergen, Norway, Department of Psychiatry, University of Iceland, Reykjavik, Iceland, l o Department of Psychiatry, University of Oulo, Finland
’
I
Reactive psychosis is a common diagnosis in the Nordic countries (Norway, Sweden, Denmark, Finland and Iceland) and in several other parts of the world. In ICD-9 and DSM-111-R, the concept is defined more narrowly than in the Nordic tradition. In this study we examined the interrater reliability of the Nordic concept by the case-summary method between clinicians from 9 university departments in the Nordic countries. The results show that Nordic psychiatrists have a reasonably reliable concept of reactive psychosis, and that this psychosis can be diagnosed as reliably as schizophrenia and affective psychosis.
Reactive psychosis as a diagnostic category was described by German psychiatrists toward the end of the nineteenth century. In General psychopathology, Jaspers (1) separated “true reactions” from other functional psychoses. Reactive psychosis had a content that reflected the life event, and it would not manifest itself without the event. The course depended on the development and duration of the event. The concept was introduced to Scandinavian psychiatrists especially through the work of Wimmer in Denmark, which was presented at the first Nordic congress for psychiatrists in 1913. In his monograph, Wimmer (2) gave the following definition: By reactive psychoses we mean various clinically independent psychoses that are characterized as follows. They are caused by psychic traumas that hit a predisposed individual. These traumas are decisive for the onset of the psychosis, the course (remissionintermission-exacerbation) and the recovery. The psychosis in form and content more or less directly and completely reflects the triggering psychic trauma in an understandable way. To these criteria we can add that these disorders mostly have a favorable outcome, and especially that they do not lead to dementia.
Key words: reactive psychosis; schizophrenia; affective disorder; nosology Alv A. Dahl, MD, Department of Psychiatry, Oslo University, P.O. Box 85, Vinderen, N-03 19 Oslo, Norway Accepted for publication February 1, 1992
The first follow-up study of reactive psychosis was conducted by the Danish psychiatrist Fzrgeman (3) on a sample of 170 patients from Wimmer’s clinic in Copenhagen. At follow-up 16-19 years later, he was able to verify the diagnosis in 70 patients, about half of the cases with reactive psychosis. The other half had developed schizophrenia or manic-depressive psychosis over the years. This heterogeneity of the reactive psychoses at follow-up led Slater to reject the concept (4). Also, the word psychogenic, which is often connected to these psychoses, was criticized by Lewis (5). This explains why the concept of reactive psychosis did not catch on in the Englishspeaking countries. However, the concept had widespread use in Russia, Japan, German-speaking countries, France and the Nordic countries. This leads to the inclusion of reactive psychoses under other psychoses in ICD-8 (6), despite opposition from the representatives of the United Kingdom and the United States. ICD-9 (7) points to a narrow concept of reactive psychoses:
55
Hansen et al. Categories 298.0-298.8 should be restricted to the small group of psychotic conditions that are largely or entirely attributable to a recent life experience. They should not be used for the wider range of psychoses in which environmental factors play some (but not the major) part in aetiology.
The concept of reactive psychosis was made still narrower in DSM-111-R (8). A diagnosis of brief reactive psychosis requires the appearance of psychotic symptoms shortly after and apparently in response to events that would be markedly stressful to anyone, a duration of less than 1 month and full return to the premorbid level of functioning. As pointed out by Jauch & Carpenter (9), this defines a very restricted category. In the ICD-10 Clinical Diagnostic Guidelines (lo), acute and transient psychotic disorders, which include stress-related disorders, have a rather narrow definition. The first psychotic symptoms develop within 2 weeks of an event that would be regarded as stressful to most patients. Complete recovery usually occurs within 1 month. For the schizophrenia-like subtype, the duration has to be less than 1 month and for the delusional and polymorphic subtypes less than 3 months. Neither DSM-111-R nor ICD-10 includes the affective syndromes. These trends in international classification are in contrast to the broad concept of reactive psychoses used in the Nordic countries. However, even within the Nordic countries at least 4 concepts of “reactive psychosis” had been in use (1 1): 1) Reactive psychosis is a functional psychosis that is not clearly schizophrenic, manic-depressive or paranoid type (12). 2) Reactive psychosis is a purely psychogenic psychosis caused by a traumatic psychological situation (13). 3) Reactive psychosis is a functional psychosis with good outcome (14). 4) Reactive psychosis is characterized by an interaction of trauma and vulnerability (15). Should Nordic psychiatrists keep the tradition of reactive psychosis or join the international classification? To answer this, it is important to know how consistent and reliable Nordic psychiatrists are in using this diagnosis. This study, therefore, examines 3 relevant questions by use of the case-summary method: What is the interrater reliability of the diagnosis of reactive psychosis within and between the Nordic countries? Does the interrater reliability of reactive psychosis differ from that found for schizophrenia or affective psychosis? What is the interrater reliability of various functional psychoses in DSM-111-R compared with ICD-9 and national classifications?
Material and methods
Dahl and Hansen prepared 30 case histories of patients treated for functional psychosis at the Department of Psychiatry, University of Oslo. Dahl and Hansen and the clinicians who treated the patients diagnosed these cases independently according to ICD-9. Fifteen cases (base rate 0.50) had a diagnosis of 298.0-298.8 reactive psychosis ( 5 each of affective, confusional and paranoid subtype). Five cases had 295 schizophrenia, 5 296 affective psychosis and 5 295.7 schizoaffective schizophrenia (base rate 0.17 each) according to consensus of the clinicians and Dahl and Hansen. These diagnoses fulfill Spitzer’s LEAD standard (16), as they are based on longitudinal observation and expert clinicians who had all data, and they are considered as master ratings. The departments of psychiatry at 2 university hospitals in each country participated in the study, except for Iceland, which has only one university (Denmark: Arhus and Copenhagen; Sweden: Uppsala and Gothenburg; Norway: Oslo and Bergen; Finland: Oulo and Helsinki; and Iceland: Reykjavik). An experienced psychiatrist at each site diagnosed the 30 cases according to 3 classification systems: ICD-9, DSM-111-R and national tradition, the latter defined as the traditional diagnostic practice used for the various functional psychoses in each country. The psychiatrists were also asked to indicate their diagnostic confidence on each case on a 3-point scale. A score of 1 meant a certain, typical case, a score of 2 represented a probable case with minor uncertainty and a score of 3 meant that the case was uncertain and doubtful. Cohen’s kappa was used for the statistical analysis. The intercenter reliability was calculated by the formula for 2 raters and polychotomous data (17). Table 1. Sensitivity, specificity and number of the ICD-9 diagnosis of reactive psychosis and mean confidence ratings of the centers compared with the master rating
No. of cases Center
Oslo Bergen Arhus Copenhagen Uppsala Gothenburg Oulo Helsinki Reykjavik
Sensitivity
Specificity
0.53 0.53
1.00 1.00
0.47 0.93 0.47
1.00
of reactive psychosis
Mean confidence rating
8
12
1.83 1.50 1.75 1.34 1.44 1.41 1.18 1.74 1.53 1.52
8 7 26 7 10
0.73
0.20 0.87 0.93 0.93 1.00 0.93
Mean
0.56
0.87
10.1
Median
0.53
0.93
8
0.60 0.40 0.40
7 6
Reliability of reactive psychoses Table 2. Kappa values for interrater reliability between various centers Norway
Master Oslo Bergen Arhus Copenhagen Uppsala Gothenburg Helsinki Espoo
Denmark
Sweden
Finland
Iceland
Oslo
Bergen
Arhus
Copenhagen
Uppsala
Gothenburg
Helsinki
Espoo
Reykjavik
0.73
0.73 0.76
0.65 0.76 0.76
0.53 0.41 0.30 0.27
0.53 0.52 0.71 0.71 0.22
0.73 0.84 0.68 0.68 0.49 0.80
0.56 0.59 0.67 0.67 0.30 0.55 0.52
0.85 0.80 0.72 0.64 0.46 0.60 0.79 0.56
0.80 0.76 0.76 0.76 0.43 0.74 0.60 0.68 0.80
Since Iceland had only one site, Reykjavik was compared with the master ratings. A kappa value above 0.75 was considered as high interrater reliability, between 0.50 and 0.74 medium and below 0.50 low. Results
For ICD-9 compared with master ratings, the sensitivity for reactive psychosis was 0.50 and above at 5 sites (Table 1). The specificity was over 0.87 at all sites except Copenhagen, where it was only 0.20. The master rating diagnosed 15 cases of reactive psychosis. The rater in Copenhagen diagnosed 26 such cases; for the other sites the number varied between 6 and 12 (mean 10.1). The kappa values for the intercenter reliability of reactive and nonreactive psychosis varied between 0.23 and 0.84 between sites (Table 2). Thirteen of 45 ratings (29%) showed a kappa value of 0.75 or higher. Kappa values between 0.50 and 0.74 were found for 23 ratings (51 %); 9 ratings (20%) showed a kappa value below 0.50. However, all low intercenter reliability ratings were connected with the rater in Copenhagen. If Copenhagen is not included, 36% of the ratings had high and 64% medium intercenter reliability on the distinction between reactive and nonreactive psychosis. When percentage agreement among raters is applied, the agreement at or above 80% was higher for nonreactive than for reactive psychosis (P< 0.001). When reactive psychosis is compared with schizophrenia, schizoaffective psychosis and affective psychosis, the percentage agreement of reactive psychosis spread between the low agreement found in schizoaffective psychosis and the high agreement found in affective psychosis (Table 3). The raters were quite confident about the diagnosis of reactive psychosis, since the mean confidence rating for these cases was 1.47. This was lower than the mean (1.53) for nonreactive psychosis in ICD9 (P
