The dexamethasone suppression test in affective illnesses and schizophrenia: relationship with psychotic symptoms

Schizoaffective disorder diagnosed according to different diagnostic criteria--systematic literature search and meta-analysis of key clinical characteristics and heterogeneity

BACKGROUND

Schizoaffective disorder is viewed as a heterogeneous diagnosis among psychotic illnesses. Different diagnostic systems differ in their definition with DSM (-IIIR, -IV, and -V) providing a narrower definition than RDC and ICD-10. It is unclear whether this difference is reflected in patient samples diagnosed according to different diagnostic systems.

METHODS

Exploratory study based on a systematic review of studies of schizoaffective disorder samples diagnosed by either RDC and ICD-10 (group of "broad criteria") or DSM-IIIR and -IV ("narrow criteria"); comparison (by Mann-Whitney-U-tests) of key characteristics, such as age, number of hospitalizations, or scores in psychometric tests, between more broadly and more narrowly defined schizoaffective disorder samples using standard deviations as a measurement of heterogeneity as well as weighted means and percentages. To reduce selection bias only studies including schizoaffective patient samples together with affective disorder and schizophrenia samples were selected.

RESULTS

55 studies were included, 14 employing RDC, 4 ICD-10, 20 DSM-IIIR, and 17 DSM-IV. Thirteen characteristics were compared: patients diagnosed according to broader criteria had fewer previous hospitalizations (2.2 vs. 5.4) and were both less often male (42 vs. 51%) and married (21 vs. 40%). Heterogeneity was similar in both groups but slightly higher in RDC and ICD-10 samples than in DSM-IIIR and -IV-samples: +4% regarding demographic and clinical course data and +13% regarding psychometric tests (pooled SD).

LIMITATIONS

Secular trends and different designs may have confounded the results and limit generalizability. Some comparisons were underpowered.

CONCLUSIONS

Differences in diagnostic criteria are reflected in key characteristics of samples. The association of larger heterogeneity with wider diagnostic criteria supports employing standard deviations as a measurement of heterogeneity.

Heterogeneity of schizoaffective disorder compared with schizophrenia and bipolar disorder

OBJECTIVE

Low diagnostic reliability, the need to meet criteria of two disorders, and its status as residual diagnosis in clinical practice led us to hypothesize that schizoaffective disorder (SAD) is characterized by considerable heterogeneity, particularly in comparison with schizophrenia (SZ) and bipolar disorder (BD). As this has not been investigated the aim of this study is to test whether heterogeneity is larger in SAD than in SZ and BD.

METHOD

Systematic search for studies simultaneously comparing all three diagnoses regarding demographic, clinical, psychometric (clinical rating scales and IQ tests), and biological parameters; comparison of heterogeneity as measured by standard deviation (SD).

RESULTS

Standard deviation of SAD samples (N = 47) was smaller than in both differential diagnoses. SDs were 7% higher in BD than in SAD (SZ: 2% higher); in studies employing DSM-IIIR/-IV pooled SD was 4% higher in BD (8% lower in SZ). Differences between diagnoses were limited to the comparison of SAD and BD, and became smaller when only psychotic BD was considered.

CONCLUSION

Heterogeneity of SZ and BD is not smaller than that of SAD. SAD seems not to be more diverse than other functional psychoses. Results are preliminary because of the novelty of the approach and to the small number of studies.

Characteristics of patients diagnosed with schizoaffective disorder compared with schizophrenia and bipolar disorder

OBJECTIVES

Information on basic demographic and clinical characteristics of schizoaffective disorder is sparse and subject to sampling bias and low diagnostic reliability. In the present study we aimed to: (i) estimate the demographic and clinical descriptors in schizoaffective disorder patients and (ii) compare the findings with those with schizophrenia and bipolar disorder.

METHODS

To minimize sampling bias and low reliability, we systematically reviewed studies that simultaneously compared schizoaffective, schizophrenia, and bipolar disorder patients. We estimated demographic, clinical, and psychometric characteristics based on weighted pooling, and compared disorders by meta-analysis. We also estimated whether schizoaffective disorder is closer to schizophrenia or to bipolar disorder.

RESULTS

We identified 50 studies that included 18312 patients. Most characteristics of the 2684 schizoaffective disorder patients fell between those of 4814 diagnosed with bipolar disorder and 10814 with schizophrenia. However, the schizoaffective group had the highest proportion of women (52%), had the youngest age at illness onset (23.3 ± 3.8 years), and had the highest standardized ratings of psychosis and depression. Differences in pooled parameters between schizoaffective versus schizophrenia and versus bipolar disorder subjects were similar. Values for patients with schizoaffective disorders mostly were intermediate between schizophrenia and bipolar disorder. However, the majority of studies showed schizoaffective patients to be more like schizophrenia than bipolar disorder patients in seven out of nine demographic and clinical categories as well as in five out of eight psychometric measures. These results remained similar when we restricted the analyses to studies with psychotic bipolar disorder patients only or to studies using the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IIIR and DSM-IV only.

CONCLUSIONS

The present study provided estimates of important characteristics of schizoaffective disorder - as balanced as possible in summarizing the findings from observational studies as unbiased as possible. The results did not support the hypothesis that schizoaffective disorder is primarily an affective disorder. The stronger resemblance of schizoaffective disorder to schizophrenia than to bipolar disorder needs further investigation.

A randomised controlled study of risperidone and olanzapine for schizophrenic patients with neuroleptic-induced acute dystonia or parkinsonism

The objective of this study was to compare the effects of risperidone and olanzapine in schizophrenic patients with intolerant extrapyramidal side effects (EPS) on first generation antipsychotics. We conducted an 8-week, rater-blinded, flexible dose study. Seventy patients with schizophrenia, who met the DSM-IV research criteria of having neuroleptic-induced acute dystonia or parkinsonism, were randomly assigned to risperidone or olanzapine group. The primary outcome was a comparison of the incidence of concomitant anticholinergic drugs usage between the groups to manage their acute dystonia and parkinsonism. The average doses of risperidone and olanzapine from baseline to study end point were 1.8-3.5 mg/day and 7.7-11.7 mg/day, respectively. There were no significant differences in demographic data, severity of EPS or psychotic symptoms between the groups at baseline assessment. Patients taking risperidone had significantly higher incidence of using anticholinergic drugs to manage acute dystonia or parkinsonism overall during the study (OR = 5.17, 95%CI = 1.49-17.88, P = 0.013). There was no significant between-group difference in the changing of rating scales of EPS and psychotic symptoms. The results of our study favour olanzapine as a better choice in schizophrenic patients with intolerant EPS. Double-blinded, fixed dose and different ethnical study for EPS-intolerant schizophrenic patients is needed to confirm the results of our study.

A systematic review of hypothalamic-pituitary-adrenal axis function in schizophrenia: implications for mortality

There is convincing evidence that environmental stress plays a significant role in modifying both mental and physical health. The biological mechanisms linking stress to ill health are not fully understood, but significant evidence points to a central role of the stress axes; the hypothalamic- pituitary-adrenal (HPA) axis and the sympathetic nervous system. Together these two systems link the brain and the body and are crucial in maintaining homeostasis as well as improving an organism's survival chances in the face of environmental challenge. There is evidence of altered HPA axis function in people with a range of mental disorders, and this may in part explain the poor physical health of people with psychotic, mood and anxiety disorders. This paper systematically reviews HPA axis function in people with schizophrenia and relates this to the pattern of physical health seen in this disease. In summary, the evidence suggests people with schizophrenia can experience both hyper- and hypo-function of the HPA axis. It is likely that this contributes to the pattern of poor physical health and premature mortality suffered by people with schizophrenia, in particular the high rates of cardiovascular and metabolic disturbance.

Stress and HPA-axis functioning in young people at ultra high risk for psychosis

It is thought that hypothalamic-pituitary-adrenal (HPA) axis functioning mediates between the experience of stress and development of psychotic symptoms. This study aimed to evaluate this model in a cohort of young people at ultra high risk (UHR) of psychosis. Information about the experience of psychological symptoms and recent stressful experiences was obtained from 23 young people who met UHR criteria. Plasma samples were taken to assess cortisol and glucocorticoid receptor numbers, and an MRI scan was also performed. Plasma cortisol levels were significantly and positively correlated with the experience of 'hassles' but not with the experience of stressful life events. Significant positive associations were also found between plasma cortisol levels and level of depression and anxiety. No significant relationships were found between plasma cortisol level and global psychopathology, psychotic symptomatology, functioning or pituitary and hippocampal volumes. These results suggest that the number of hassles experienced by young people at UHR of psychosis could be an important factor in raising their cortisol levels, which might, in turn, affect the severity of depressive and anxiety symptoms. No other relationships were found between plasma cortisol levels and the experience of psychotic symptoms, functioning or hippocampal and pituitary volumes. These results indicate possible impairment in HPA-axis functioning in the early stages of psychotic illness, but further investigation of the relationships between these parameters is required.

Stress, the hippocampus and the hypothalamic-pituitary-adrenal axis: implications for the development of psychotic disorders

OBJECTIVE

The experience of stress is commonly implicated in models of the onset of psychotic disorders. However, prospective studies investigating associations between biological markers of stress and the emergence of psychotic disorders are limited and inconclusive. One biological system proposed as the link between the psychological experience of stress and the development of psychosis is the Hypothalamic-Pituitary-Adrenal (HPA) axis. This paper summarizes and discusses evidence supporting a role for HPA-axis dysfunction in the early phase of schizophrenia and related disorders.

METHOD

A selective review of psychiatric and psychological research on stress, coping, HPA-axis, the hippocampus and psychotic disorders was performed, with a particular focus on the relationship between HPA-axis dysfunction and the onset of psychotic disorders.

RESULTS

Individual strands of past research have suggested that the HPA-axis is dysfunctional in at least some individuals with established psychotic disorders; that the hippocampus is an area of the brain that appears to be implicated in the onset and maintenance of psychotic disorders; and that an increase in the experience of stress precedes the onset of a psychotic episode in some individuals. Models of the onset and maintenance of psychotic disorders that link these individual strands of research and strategies for examining these models are proposed in this paper.

CONCLUSIONS

The current literature provides some evidence that the onset of psychotic disorders may be associated with a higher rate of stress and changes to the hippocampus. It is suggested that future research should investigate whether a relationship exists between psychological stress, HPA-axis functioning and the hippocampus in the onset of these disorders. Longitudinal assessment of these factors in young people at 'ultra' high risk of psychosis and first-episode psychosis cohorts may enhance understanding of the possible interaction between them in the early phases of illness.

The dexamethasone suppression test and sleep electroencephalogram in nonbipolar major depressed inpatients: a multivariate analysis

BACKGROUND

The present study further examined relationships between postdexamethasone cortisol plasma values and sleep electroencephalogram (EEG) parameters.

METHODS

The dexamethasone suppression test (DST) and polysomnographic recordings were performed in a sample of 300 inpatients with primary major depressive disorder (MDD) (102 men and 198 women, mean age 44 +/- 12 years, range 20-74 years) consecutively admitted to Erasme Hospital (Brussels, Belgium) between 1981 and 1992.

RESULTS

The DST was abnormal in 40% of the sample. Postdexamethasone cortisol plasma values at 4:00 PM were significantly influenced by age, but not by gender. They were also significantly and positively correlated with weight loss, total scores on the Hamilton Depression Rating Scale, total scores on the Newcastle Scale, percentage of awakenings during sleep, and percent of stage 1. They were significantly and negatively correlated with percent of stage 2, slow-wave sleep, and REM sleep. Multiple regression analyses were conducted in two successive steps. First among clinical variables, only age and depressive symptom severity remained correlated with postdexamethasone plasma cortisol values. In the second step, with age and severity held constant, postdexamethasone plasma cortisol values were positively associated with amount of wake time and stage 1, and negatively with amount of slow-wave sleep.

CONCLUSIONS

These findings provide further indirect support for an overarousal state in MDD with sympathoadrenal system hyperactivity and impaired sleep continuity. They also underline the importance of taking into account various clinical confounding factors in the interpretation of both DST and sleep EEG results.

Hypothalamic-pituitary-adrenal axis function and suicidal behavior in depression

Hypothalamic-pituitary-adrenal (HPA) axis function was examined in relation to suicidal behavior in depression. There were no significant differences between depressed patients who had or had not attempted suicide for either cerebrospinal fluid concentrations of corticotropin-releasing hormone, plasma cortisol levels predexamethasone or postdexamethasone, or for urinary-free cortisol outputs. However, depressed patients who had made a violent suicide attempt had significantly higher 4 PM and maximum postdexamethasone plasma cortisol levels, and significantly more of them were cortisol nonsuppressors than patients who had made nonviolent suicide attempts. A 5-year follow-up was carried out. There were no significant differences on indices of HPA function between depressed patients who did or did not reattempt suicide during the follow-up or who had never attempted suicide. These results suggest the possibility that dysregulation of the HPA axis may be a determinant of violent suicidal behavior in depression.

Dexamethasone suppression test in schizophrenia: relationship to symptomatology, ventricular enlargement, and outcome

To relieve confusion about the clinical correlates and prognostic implications of the dexamethasone suppression test (DST) in schizophrenia, we conducted a DST in 44 schizophrenic inpatients at drug-free baseline and approximately 4 weeks after neuroleptic treatment. Patients were rated on positive, negative, and depressive symptoms at both times. A head computed tomography (CT) scan was performed and measures of ventricle-brain ratio (VBR) obtained. Clinical improvement was monitored at four weeks, and longer-term outcome assessed at 1 year. Seventeen of the 44 patients were DST nonsuppressors at baseline, and five of these remained nonsuppressors at 4 weeks posttreatment. Postdexamethasone plasma cortisol levels were correlated with negative symptoms at baseline (r = 0.45; p less than 0.01), but not after 4 weeks of neuroleptic treatment. Postdexamethasone plasma cortisols were not related to global severity, positive, or depressive symptoms at either timepoint or to VBR. Persistent nonsuppression was associated with poor outcome, but baseline postdexamethasone cortisol levels were unrelated to outcome at 4 weeks and 1 year. The literature on DST in schizophrenia is reviewed and attempts are made to reconcile discrepant findings and to discuss pathophysiological implications.

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.

The effect of diagnosis and age on the DST: a metaanalytic approach

The authors present new data on the results of the pretreatment Dexamethasone Suppression Test (DST) in 164 drug-free inpatients, as well as on the effects of age on postdexamethasone cortisol values. Nonsuppression rates were 18% in schizophrenic patients (n = 44), versus 46% in patients with a major depression (n = 56). In addition, a significant correlation was found between age and the 4:00 PM postdexamethasone cortisol value among the depressed patients (r = 0.33). The authors then applied a metaanalysis to summarize 25 other studies that have addressed the schizophrenia/major depression dichotomy as it relates to the DST outcome. Nonsuppression rates were consistently different in schizophrenic patients (19%) when compared to patients with a major depression (51%) or normal controls (7%). These differences were highly significant as measured by the Mantel-Haenszel chi-square statistic. A metaanalysis applied to a series of correlations obtained from 14 other studies reporting an age/postdexamethasone cortisol relationship in affective patients indicated a modest, but significant correlation (r = 0.24) in a total of 1284 patients (p less than 1 x 10(-8)).