A comparison of cognitive profiles in schizophrenia and other psychiatric disorders

Social cognition and interaction training for major depression: A preliminary study

The present work investigated the efficacy of social cognition and interaction training (SCIT) for patients with major depression. Thirty first-episode patients with major depression who received the SCIT plus the treatment-as-usual (i.e., SCIT + TAU group) were compared with twenty-nine patients who only received treatment-as-usual (i.e., TAU group). Patients received SCIT showed a significantly greater improvement on emotion perception, theory of mind, and attributional styles from baseline to follow-up assessments, with a significant reduction of severity of depressive symptoms, compared to those in TAU group. The preliminary findings indicate that SCIT is a feasible and promising method to improve social cognition for patients with major depression.

Cognitive impairment in schizophrenia and depression: A comparison of stability and course

Cognitive deficits are clinically relevant features in schizophrenia and depression, yet little comparative data on changes in both disorders is available. This study compares cognitive performance of inpatients with schizophrenia (N = 52) and unipolar major depression (N = 67) during psychiatric treatment, assessing performance twice: after admission to hospital (acute) and prior to discharge (postacute) on average seven weeks later. A group of healthy controls was tested at comparable intervals. Data was analyzed using a multivariate linear model. Patients with schizophrenia and depression showed significantly impaired performance compared to healthy controls. On follow-up both patient groups showed improved performance. Contrary to expectation, patients with schizophrenia showed greater improvement in verbal memory, visual memory, and psychomotor speed than depressive patients. Verbal fluency presented as a possible candidate to differentiate between both disorders. Similar profiles of generalized cognitive deficits were observed in both patient-groups on acute and postacute assessment, which might indicate trait-like deficits with persistent functional implications in both disorders. Findings do not support assumptions of greater cognitive impairment in schizophrenia compared to depression. A distinction of the disorders on the grounds of cognitive functioning seems to be less specific than presumed.

Effects of tobacco smoking on neuropsychological function in schizophrenia in comparison to other psychiatric disorders and non-psychiatric controls

BACKGROUND AND OBJECTIVES

Compared to the general population cigarette smoking prevalence is elevated in psychiatric disorders such as schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MDD). These disorders are also associated with neurocognitive impairments. Cigarette smoking is associated with improved cognition in SZ. The effects of smoking on cognition in BD and MDD are less well studied.

METHODS

We used a cross-sectional design to study neuropsychological performance in these disorders as a function of smoking status. Subjects (N = 108) were SZ smokers (n = 32), SZ non-smokers (n = 15), BD smokers (n = 10), BD non-smokers (n = 6), MDD smokers (n = 6), MDD non-smokers (n = 10), control smokers (n = 12), and control non-smokers (n = 17). Participants completed a neuropsychological battery; smokers were non-deprived.

RESULTS

SZ subjects performed significantly worse than controls in select domains, while BD and MDD subjects did not differ from controls. Three verbal memory outcomes were improved in SZ smokers compared with non-smokers; smoking status did not alter performance in BD or MDD.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

These data suggest that smoking is associated with neurocognitive improvements in SZ, but not BD or MDD. Our data may suggest specificity of cigarette-smoking modulation of neurocognitive deficits in SZ.

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.

Neuropsychological functioning in inpatients with major depression or schizophrenia

BACKGROUND

Studies that compare neuropsychological functioning in inpatients with mood disorder or schizophrenia come to heterogeneous results. This study aims at investigating the question whether there are different neuropsychological test profiles in stabilised post-acute inpatients with affective disorders or schizophrenia.

METHOD

We were interested in evaluating impairment in specific areas of cognitive functioning in patients with schizophrenia or depression. In clinical reality, patients with depression and schizophrenia are often treated together with little attention to their specific needs. 74 patients with major depression and 38 patients with schizophrenia were assessed in a comprehensive neuropsychological battery. All patients were in a post-acute stage of their illness, i.e. remission of acute symptoms.

RESULTS

In spite of a comparable mean score of psychopathological symptoms in the Brief Psychiatric Rating Scale-Expanded (BPRS-E) as well as in the Global Assessment Functioning Scale (GAF), patients with depressive disorder showed significantly better results in verbal and visual short-term memory, verbal fluency, visual-motor coordination, information processing in visual-verbal functioning and selective attention compared to patients with schizophrenia. No significant differences between both samples were found in practical reasoning, general verbal abstraction, spatial-figural functioning, speed of cognitive processing.

CONCLUSIONS

These results show that there are differences in scores in psychopathology (BPRS-E, GAF) in patients with affective disorders or schizophrenia and different neuropsychological test profiles in the post-acute stage of their illness.

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.

Neurological soft signs in adolescents with first episode psychosis: two-year followup

Neurological soft signs were assessed in 24 first episodes of early onset psychosis and 30 healthy adolescents over a 2-year period. Patients presented more neurological soft signs than controls and showed a significant decrease in some Neurological Evaluation Scale scores over the followup period. This decrease in the patient group was influenced by changes in symptomatology.

Is schizoaffective disorder a distinct categorical diagnosis? A critical review of the literature

Considerable debate surrounds the inclusion of schizoaffective disorder in psychiatric nosology. Schizoaffective disorder may be a variant of schizophrenia in which mood symptoms are unusually prominent but not unusual in type. This condition may instead reflect a severe form of either major depressive or bipolar disorder in which episode-related psychotic symptoms fail to remit completely between mood episodes. Alternatively, schizoaffective disorder may reflect the co-occurrence of two relatively common psychiatric illnesses, schizophrenia and a mood disorder (major depressive or bipolar disorder). Each of these formulations of schizoaffective disorder presents nosological challenges because the signs and symptoms of this condition cross conventional categorical diagnostic boundaries between psychotic disorders and mood disorders. The study, evaluation, and treatment of persons presently diagnosed with schizoaffective may be more usefully informed by a dimensional approach. It is in this context that this article reviews and contrasts the categorical and dimensional approaches to its description, neurobiology, and treatment. Based on this review, an argument for the study and treatment of this condition using a dimensional approach is offered.

Does diagnostic classification of early-onset psychosis change over follow-up?

OBJECTIVE

To examine the diagnostic stability and the functional outcome of patients with early-onset psychosis (EOP) over a 2-year follow-up period.

METHODS

A total of 24 patients (18 males (75%) and 6 females (25%), mean age +/- SD: 15.7 +/- 1.6 years) with a first episode of EOP formed the sample. Psychotic symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS). Social disability was measured with the Global Assessment of Functioning (GAF) disability scale. Diagnosis was assessed using the Kiddie-Sads-Present and Lifetime Version (K-SADS-PL), according to DSM-IV criteria. All diagnoses were re-assessed after 1 year and 2 years.

RESULTS

Schizophrenia had the highest prospective consistency (100% predictive value), while diagnostic stability was moderate for bipolar disorder (71.4%), and low for schizoaffective disorder (50%), schizophreniform and brief psychosis (50%), and psychosis not otherwise specified (NOS) (16.7%). The agreement between the baseline diagnoses and the 1-year follow-up diagnoses was 54.2%, whereas between the 1-year follow-up and the 2-year follow-up, it rose to 95.7%. Regardless of diagnosis, baseline negative symptoms were the only significant predictor of level of functioning at the 2-year follow-up (p = 0.010).

CONCLUSION

Our results highlight the primacy of the first-year follow-up diagnosis in predicting diagnostic stability of EOP.

Cognitive complexity of self-administered depression measures

BACKGROUND

Self-administered depression measures are important tools for research and practice, but their utility depends on the quality of the measurements they yield. Respondent comprehension is essential for meaningful measurement and prior studies have used readability indices to assess comprehensibility. Readability, however, is only one aspect of comprehension and empirical evidence shows that comprehension and measurement quality decrease as the cognitive complexity of standardized questions increases. Thus, cognitive complexity may provide a useful guide for selecting measures to maximize measurement quality.

METHODS

This study compared the cognitive complexity of 15 self-administered depression measures. Four aspects of cognitive complexity (length, readability, linguistic problems and number) were combined to characterize overall complexity.

RESULTS

Measures varied considerably. The most cognitively complex measures, likely to be most difficult to comprehend, were the Inventory to Diagnose Depression (IDD), the Hamilton Depression Inventory (HDI, Full and Short Versions), and the Beck Depression Inventory (BDI, BDI-II, BDI-PC). The least complex measures, likely to be easiest to comprehend, were the Harvard National Depression Screening Day Scale (HANDS), the Revised Hamilton Rating Scale for Depression Self-Report Problem Inventory (RHRSD) and the Zung Self-Rated Depression Scale (SDS). This multidimensional approach to assessing complexity and comprehensibility yielded different results than readability indices alone.

LIMITATIONS

This study did not include all self-administered depression measures and did not examine the relationship of cognitive complexity to actual responses to depression measures.

CONCLUSIONS

Since cognitive complexity is likely to limit comprehension and reduce measurement accuracy, it merits consideration in selection of self-administered depression measures.

Enhanced semantic priming in schizophrenia: a computer model based on excessive pruning of local connections in association cortex

BACKGROUND

Many studies have found that people with schizophrenia exhibit abnormally high levels of semantic priming. Post-mortem and neuroimaging studies of schizophrenia suggest a reduction of neuritic processes (dendrites and synapses).

AIMS

To demonstrate that reductions in neuritic processes can produce excessive priming in patients with schizophrenia.

METHOD

Associative memory was simulated using a computer-based neural network system consisting of two interactive neural groups, one coding for individual memories and the other for the category to which each memory belonged.

RESULTS

Variation of a single parameter determining the density of local connections within the two neuronal groups gave a close approximation to levels of memory access and semantic priming previously reported in normal subjects and in patients with schizophrenia.

CONCLUSIONS

This study suggests that schizophrenia arises from excessive pruning of local connections in association cortex. Its findings shed light on the mechanisms underlying cognitive priming more generally, and how it might emerge developmentally.

Memory and organizational strategies in chronic and acute schizophrenic patients

The memory profile of acute and chronic schizophrenic patients was examined according to the information processing model, with which encoding, retention and retrieval processes of these patients were compared. The effects of an external organizational strategy on their verbal learning and memory were also examined. Twenty chronic and 20 acute schizophrenic patients were tested with a list learning task consisting of a random (i.e., words presented randomly) and a blocked (i.e., words presented in clusters) word-list. The schizophrenic patients, as compared with age- and education-matched normal control subjects, demonstrated impaired learning, and the duration of their illness was not a significant factor in the severity of their learning impairment. However, the acute and chronic schizophrenic patients seem able to retain most of the newly acquired materials, regardless of the presentation format, after 30 min. In addition, the learning and subjective organizational strategy of the chronic patients, but not that of the acute patients, improved significantly by the blocked presentation. However, semantic organization could facilitate both the chronic and acute schizophrenic patients to retain more newly learned items.

Predictive validity of the Neurobehavioural Cognitive Status Examination (NCSE) in a post-acute rehabilitation setting

Within the context of a post-acute rehabilitation setting, association and agreement between results from the Neurobehavioural Cognitive Status Examination (NCSE) and from the neuropsychological (NP) evaluation are examined. All participants (n = 48) had sustained a severe traumatic brain injury and NCSE testing preceded NP testing by an average of 1 month. A significant relationship and fair classification agreement (i.e. presence or absence of cognitive impairment) was found between the overall results from NCSE and NP evaluation. Significant relationships were also observed between most NCSE subtests and paired NP tests thought to be assessing the same cognitive domains. However, the classification agreement (i.e. the presence or absence of deficient performance) between most NCSE subtests and paired NP tests was poor. The findings are discussed from the standpoint of individual treatment planning.