Response to the dexamethasone suppression test in schizoaffective disorder, depressed type

Does schizoaffective disorder really exist? A systematic review of the studies that compared schizoaffective disorder with schizophrenia or mood disorders

BACKGROUND

Since its first definition in the literature, schizoaffective disorder (SAD) has raised a considerable controversy regarding its clinical distinction from schizophrenia (SCH) and mood disorders (MD) as well as its validity as an independent nosological category.

OBJECTIVE

Investigate the validity of SAD as a discrete nosological category and its relationship with SCH and MD.

METHOD

A systematic literature review of clinical trial that compared SAD with SCH and/or MD patients was carried out throughout MEDLINE, psycINFO, Cochrane Library, SCIELO and LILACS databases.

RESULTS

Evaluation of demographic characteristics, symptomatology, other clinical data, dexamethasone suppression test, neuroimage exams, response to treatment, evolution and family morbidity indicated that SAD occupies an intermediate position between SCH and MD. Literature review also failed to indicate a clear cut distinction between SAD and SCH or MD.

DISCUSSION

Present analysis indicated that SAD cannot be interpreted as atypical forms of SCH or MD. SAD also does not appear to represent a SCH and MD comorbidity or yet an independent mental disorder. It is argued that SAD might constitute a heterogeneous group composed by both SCH and MD patients or a middle point of a continuum between SCH and MD.

Major depression with mood-congruent psychotic features: a distinct diagnostic entity or a more severe subtype of depression?

The nosological status of major depression with mood-congruent psychotic features was explored by a cross-sectional demographic, clinical and biological assessment and a 7-year prospective follow-up of 2 samples of patients fulfilling, respectively, DSM-III criteria for this condition and for major depression without psychotic features. The 2 patient groups did not differ with respect to demographic and historical features, response to DST and outcome. The global severity of the index episode was greater in psychotics. All nonpsychotics and 69% of psychotics were treated with antidepressants alone or in combination with benzodiazepines, whereas the addition of neuroleptics was required only in 31% of psychotics. A tendency towards an interepisodic diagnostic stability was verified in nonpsychotics more than in psychotics, but was less pronounced than that reported by the authors advocating the nosological autonomy of delusional depression. These data support the view that major depression with mood-congruent psychotic features is not a distinct diagnostic entity, but rather a more severe depressive subtype.

Depression dexamethasone nonsuppression and negative symptoms in schizophrenia

This study compared three measures of depression in schizophrenia and their correlation with the Dexamethasone Suppression Test (DST). The degree of overlap of these three measures with negative symptoms was also examined. The Hamilton Depression Rating Scale (HDRS), the depressive syndrome score of the Present State Examination (PSE), and the Scale for the Assessment of Negative Symptoms (SANS) were administered to 50 acutely ill, hospitalized schizophrenics. Patients were diagnosed using DSM-III criteria for schizophrenia. DSM-III criteria were also used to assess the presence of a major depressive episode. Results were that DST nonsuppression was significantly associated with the presence of a major depressive episode, but not with depressive rating scale scores or with negative symptoms. It is concluded that the DST may be of value in differentiating a depressive syndrome from a negative symptom syndrome in schizophrenia.

The incidence of abnormal dexamethasone suppression in schizophrenia: a review and a meta-analytic comparison with the incidence in normal controls

Studies on dexamethasone suppression test (DST) and schizophrenia are reviewed and the incidence of nonsuppression in the group of studies on schizophrenic patients is compared to that in the group of studies on normal controls from a previous review article. The incidence of nonsuppression in schizophrenic patients (26.4%) is significantly higher than that in normal controls (5.0%). There may be a subgroup of schizophrenic patients with an increase in cholinergic functioning. The variance of the nonsuppression rates of DST were also significantly higher in patients with schizophrenia compared to normal controls. This may be due to a heterogeneity of mechanisms that is responsible for the DST non-suppression due to the heterogeneous nature of the diagnosis of schizophrenia. The possible mechanisms of abnormal and varied DST results in schizophrenia are discussed.

Dexamethasone suppression test in positive and negative schizophrenia

Fifty-four inpatients with a DSM-III diagnosis of schizophrenia were studied. Patients were divided into positive and negative subtypes of schizophrenia according to Andreasen's criteria. Blood samples were obtained from all patients for 2 consecutive days to determine plasma cortisol concentrations before and after a single administration (1 mg, p.o.) of dexamethasone at 11 p.m. The results revealed a significant increase in plasma cortisol levels in schizophrenic patients, with 40% of the patients being nonsuppressors on the dexamethasone suppression test. A higher percentage (62.5%) of patients with the negative form of schizophrenia were nonsuppressors.

Judgement of the hypothalamic-pituitary-adrenocortical function in psychiatric patients by betamethasone-induced cortisol suppressibility

Betamethasone induced cortisol suppressibility was examined in 62 drug free consecutively admitted psychiatric inpatients. Betamethasone was choosen instead of the commonly used dexamethasone, because its double half-life compared to dexamethasone and its higher tissue availability. After a base-line evaluation with blood samples drawn at 8 a.m., 4 p.m., and 11 p.m., 0.5 mg or 1.0 mg betamethasone was given orally at 11 p.m. Postbetamethasone cortisol as well as betamethasone blood levels were then measured at the same time points as on the baseline day. In the groups receiving 1.0 mg betamethasone non-depressed patients had significantly (p less than 0.05) lower postbetamethasone cortisol levels than depressed patients for each time point measured whereas 0.5 mg betamethasone did not differentiate depressed from non-depressed patients. Patients with other depressions like schizoaffective psychosis-depressive subtype- or organic brain syndrome with depressive symptomatology demonstrated similar postbetamethasone cortisol profiles as the group of patients with major depression. Betamethasone plasma concentrations differed significantly (p less than 0.001) with respect to the oral dosage with higher values for the 1.0 mg betamethasone groups.

Thyrotropin response to thyrotropin-releasing hormone in RDC schizodepressed men

Biological tests may help clarify the relationships of schizoaffective disorder to both major depressive disorder and schizophrenia. Thyrotropin-releasing hormone (TRH), 500 micrograms i.v., was administered to 14 schizodepressed, 23 schizophrenics, 41 unipolar major depressives (all by RDC) and 45 healthy controls, all males 20-67 years old with no significant differences in age, body height or weight. Results showed no differences in maximal delta TSH (dTSH max) amongst schizoaffective depressed, schizophrenia and healthy control groups (10.1 +/- 1.3, 9.2 +/- 1.1, 9.7 +/- 0.8 microU/ml, means +/- SEM respectively). Mean major depressives' dTSH max was lower than in each of the other three groups (6.2 +/- 0.4 microU/ml, P less than 0.01 for all). Utilizing a less than or equal to 5.0 microU/ml cut-off criterion for blunting, the schizodepressed had 36%, schizophrenics 44%, healthy controls 22% and major depressed 59% blunters (P less than 0.05 from other three groups). Schizodepressed patients appeared significantly different from major depressed but closer to schizophrenics (and healthy controls) on the TRH test.

Lithium prophylaxis of schizoaffective disorders: a prospective study

A prospective study was carried out in order to provide an answer to the following questions. (1) Is lithium effective as a prophylactic agent in broadly defined schizoaffective disorders? (2) Taking for granted that schizoaffective disorders represent a heterogeneous group of conditions, in which schizoaffective patients is lithium effective? (3) Are there any clinical, historical or biological predictors of response to lithium prophylaxis in schizoaffective patients? (4) What are the minimum plasma lithium levels required for effective prophylaxis in schizoaffective disorders? The study confirmed the efficacy of lithium prophylaxis in broadly defined schizoaffective disorders, but showed that this treatment is relatively ineffective in schizoaffective patients with a prominent schizophrenic-like component in their clinical picture and in those diagnosed cross-sectionally as schizodepressive. The only successful predictor of response was a previous bipolar course of the illness (which was associated with a positive outcome of prophylaxis). Plasma lithium levels in the range of 0.45-0.60 mEq/l did not prove to be useful for prophylactic purposes in schizoaffective disorders.

Prediction of outcome by historical, clinical and biological variables in schizoaffective disorder, depressed type

The usefulness of several historical, clinical and biological variables as possible predictors of outcome was tested in a sample of patients with a cross-sectional diagnosis of schizoaffective disorder, depressed type. Four historical items were found to be successful: a family history of chronic schizophrenia, the occurrence of schizophrenic symptoms at some stage of the illness in the absence of depression and an onset of the index episode as exacerbation of previous symptoms (all associated with a relatively poor outcome), and a personal history of previous manic episodes (associated with a relatively good outcome). The various aspects of the clinical picture during the index episode, as well as the response on dexamethasone suppression test, were not found to have any predictive value. These findings confirm that, in patients with a cross-sectional diagnosis of schizodepressive disorder, the previous course of the illness is of crucial importance for prognosis, and support the usefulness of a multiaxial classification of schizoaffective states, taking into account not only cross-sectional symptomatology but also course.

Nosological status of schizoaffective disorders: Theoretical models and empirical evidence

The question of the nosological status of schizoaffective disorders remains one of the most controversial issues of clinical psychiatry. There are, in fact, at least five different hypotheses about the nature of these disorders: • that they are always variants of schizophrenia, • that they are always variants of major affective disorders, • that they represent a “third psychosis” distinct from both schizophrenia and manic-depressive illness, • that they find their place in the intermediate position of a “continuum” whose poles are represented by the typical forms of schizophrenia and manic-depressive illness, • that they result from the simultaneous occurrence of a true schizophrenia and a true manic-depressive illness in the same patient. The last of these hypotheses can hardly be accepted, since it would predict an annual frequency of schizoaffective disorders of about 2 per 108, compared to the actual frequency of 2 per 105. Of the remaining four hypotheses, the first two are consistent with the Kraepelinian “dichotomic” paradigm, whereas the third and the fourth contradict this paradigm. The results of empirical investigations (that is, of family studies, outcome studies and studies on response to drug treatments in schizoaffective patients) do not provide a full support to any of the above hypotheses. What empirical evidence seems to show, instead, is that schizoaffective disorders represent a heterogeneous group of syndromes. Part of these disorders can be interpreted, upon close scrutiny, as variants of either of the major psychoses (for instance, bipolar schizoaffective States appear to be closely allied to major affective disorders). There seems to be, however, a subpopulation of schizoaffective patients which escapes the Kraepelinian dichotomic model.