A critique of narrative reviews of the evidence-base for ECT in depression.

There has been recent debate regarding the efficacy of electroconvulsive therapy in the treatment of depression. This has been based on narrative reviews that contradict existing systematic reviews and meta-analyses. In this special article, we highlight the mistakes that occur when interpreting evidence using narrative reviews, as opposed to conventional systematic reviews and meta-analyses.

Cognitive-behavioural therapy for the symptoms of schizophrenia: systematic review and meta-analysis with examination of potential bias.

BACKGROUND: Cognitive-behavioural therapy (CBT) is considered to be effective for the symptoms of schizophrenia. However, this view is based mainly on meta-analysis, whose findings can be influenced by failure to consider sources of bias. AIMS: To conduct a systematic review and meta-analysis of the effectiveness of CBT for schizophrenic symptoms that includes an examination of potential sources of bias. METHOD: Data were pooled from randomised trials providing end-of-study data on overall, positive and negative symptoms. The moderating effects of randomisation, masking of outcome assessments, incompleteness of outcome data and use of a control intervention were examined. Publication bias was also investigated. RESULTS: Pooled effect sizes were -0.33 (95% CI -0.47 to -0.19) in 34 studies of overall symptoms, -0.25 (95% CI -0.37 to -0.13) in 33 studies of positive symptoms and -0.13 (95% CI -0.25 to -0.01) in 34 studies of negative symptoms. Masking significantly moderated effect size in the meta-analyses of overall symptoms (effect sizes -0.62 (95% CI -0.88 to -0.35) v. -0.15 (95% CI -0.27 to -0.03), P = 0.001) and positive symptoms (effect sizes -0.57 (95% CI -0.76 to -0.39) v. -0.08 (95% CI -0.18 to 0.03), P<0.001). Use of a control intervention did not moderate effect size in any of the analyses. There was no consistent evidence of publication bias across different analyses. CONCLUSIONS: Cognitive-behavioural therapy has a therapeutic effect on schizophrenic symptoms in the 'small' range. This reduces further when sources of bias, particularly masking, are controlled for.

Facial emotion processing in schizophrenia: a non-specific neuropsychological deficit?

BACKGROUND: Identification of facial emotions has been found to be impaired in schizophrenia but there are uncertainties about the neuropsychological specificity of the finding. METHOD: Twenty-two patients with schizophrenia and 20 healthy controls were given tests requiring identification of facial emotion, judgement of the intensity of emotional expressions without identification, familiar face recognition and the Benton Facial Recognition Test (BFRT). The schizophrenia patients were selected to be relatively intellectually preserved. RESULTS: The patients with schizophrenia showed no deficit in identifying facial emotion, although they were slower than the controls. They were, however, impaired on judging the intensity of emotional expression without identification. They showed impairment in recognizing familiar faces but not on the BFRT. CONCLUSIONS: When steps are taken to reduce the effects of general intellectual impairment, there is no deficit in identifying facial emotions in schizophrenia. There may, however, be a deficit in judging emotional intensity. The impairment found in naming familiar faces is consistent with other evidence of semantic memory impairment in the disorder.

The neuropsychology of the schizo-obsessive subtype of schizophrenia: a new analysis.

BACKGROUND: Interest in the neuro-cognitive profile of patients with schizophrenia and co-morbid obsessive compulsive disorder (schizo-OCD) is rising in response to reports of high co-morbidity rates. Whereas schizophrenia has been associated with global impairment in a wide range of neuro-cognitive domains, OCD is associated with specific deficits featuring impaired performance on tasks of motor and cognitive inhibition involving frontostriatal neuro-circuitry. METHOD: We compared cognitive function using the CANTAB battery in patients with schizo-OCD (n=12) and a schizophrenia group without OCD symptoms (n=16). The groups were matched for IQ, gender, age, medication, and duration of illness. RESULTS: The schizo-OCD patients made significantly more errors on a task of attentional set-shifting (ID-ED set-shift task). By contrast, no significant differences emerged on the Stockings of Cambridge task, the Cambridge Gamble Task or the Affective Go/NoGo tasks. No correlation emerged between ID-ED performance and severity of schizophrenia, OCD or depressive symptoms, consistent with neurocognitive impairment holding trait rather than state-marker status. Schizo-obsessives also exhibited a trend toward more motor tics emphasizing a neurological contribution to the disorder.ConclusionOur findings reveal a more severe attentional set-shifting deficit and neurological abnormality that may be fundamental to the neuro-cognitive profile of schizo-OCD. The clinical implications of these impairments merit further exploration in larger studies.

Cognitive behavioural therapy for major psychiatric disorder: does it really work? A meta-analytical review of well-controlled trials.

BACKGROUND: Although cognitive behavioural therapy (CBT) is claimed to be effective in schizophrenia, major depression and bipolar disorder, there have been negative findings in well-conducted studies and meta-analyses have not fully considered the potential influence of blindness or the use of control interventions. METHOD: We pooled data from published trials of CBT in schizophrenia, major depression and bipolar disorder that used controls for non-specific effects of intervention. Trials of effectiveness against relapse were also pooled, including those that compared CBT to treatment as usual (TAU). Blinding was examined as a moderating factor. RESULTS: CBT was not effective in reducing symptoms in schizophrenia or in preventing relapse. CBT was effective in reducing symptoms in major depression, although the effect size was small, and in reducing relapse. CBT was ineffective in reducing relapse in bipolar disorder. CONCLUSIONS: CBT is no better than non-specific control interventions in the treatment of schizophrenia and does not reduce relapse rates. It is effective in major depression but the size of the effect is small in treatment studies. On present evidence CBT is not an effective treatment strategy for prevention of relapse in bipolar disorder.

Semantic priming in schizophrenia: systematic review and meta-analysis.

BACKGROUND: Increased semantic priming is an influential theory of thought disorder in schizophrenia. However, studies to date have had conflicting findings. AIMS: To investigate semantic memory in patients with schizophrenia with and without thought disorder. METHOD: Data were pooled from 36 studies comparing patients with schizophrenia and normal controls in semantic priming tasks. Data from 18 studies comparing patients with thought disorder with normal controls, and 13 studies comparing patients with and without thought disorder were also pooled. RESULTS: There was no support for altered semantic priming in schizophrenia as a whole. Increased semantic priming in patients with thought disorder was supported, but this was significant only in comparison with normal controls and not in comparison with patients without thought disorder. Stimulus onset asynchrony (SOA) and general slowing of reaction time moderated the effect size for priming in patients with thought disorder. CONCLUSIONS: Meta-analysis provides qualified support for increased semantic priming as a psychological abnormality underlying thought disorder. However, the possibility that the effect is an artefact of general slowing of reaction time in schizophrenia has not been excluded.

[A theoretical review of category-specific impairment, its entity and the methodological problems associated with its study]. / Revisión teórica del deterioro categorial, su entidad y los problemas metodológicos asociados a su estudio.

INTRODUCTION: Studies on category-specific claim to provide insights on structure and organization of semantic information. This type of phenomenon consists of the selective impairment of the information on a domain, for instance, living things (animals) but the sparing of nonliving things (tools), or vice versa. Despite the large number of studies purportedly documenting double dissociations between both domains, the lack of theoretical debate on how to empirically define such dissociations is unclear, e.g. how they should be evaluated and reported. DEVELOPMENT: In this work, a review of literature on category-specific and the explanatory models is showed. A critical methodological is done, on the basis of three findings: 1) lack of normal control groups in the majority of case studies; 2) the questionable utilization of double dissociations; and 3) the presence of problems due to a 'ceiling effect' in most group studies of Alzheimer disease patients. CONCLUSIONS: It is claimed that while domain specificity may be a legitimate phenomenon, the critical review of literature do not provide a strong empirical foundation for the domain fractionations claimed in this literature.

Revisión teórica del deterioro categorial, su entidad y los problemas metodológicos asociados a su estudio / A theoretical review of category-specific impairment, its entity and methodological problems associated with its study

Introducción. Los estudios sobre el deterioro de categorías específicas pretenden ofrecer luz sobre la estructura y la organización de la información semántica. Este tipo de fenómenos consiste en la pérdida selectiva de la información sobre un dominio de conocimiento, por ejemplo el de los seres vivos (animales) frente al de los seres no vivos (herramientas) o viceversa. Pese al gran número de estudios que se han centrado en las dobles disociaciones entre ambos dominios, destaca la ausencia de debates teóricos sobre cómo definir empíricamente este tipo de déficit, es decir, cómo deberían evaluarse y/o documentarse. Desarrollo. En este trabajo se ofrece una revisión de la literatura sobre el deterioro categorial y de los modelos propuestos para explicar este fenómeno. Se realiza una crítica metodológica fundamentada en tres hallazgos: 1) la ausencia de grupos de control en la mayoría de los estudios de caso; 2) el uso cuestionable de las llamadas ‘dobles disociaciones’; y 3) la existencia de problemas asociados al hallazgo de un ‘efecto techo’ en la mayoría de los estudios grupales en la enfermedad de Alzheimer. Conclusiones. Aunque el deterioro categorial parece ser un fenómeno genuino, la revisión de la bibliografía no muestra la suficiente evidencia empírica como para legitimar el fraccionamiento de dominios propuesto en esta área de conocimiento

Introduction. Studies on category-specific claim to provide insights on structure and organization of semantic information. This type of phenomenon consists of the selective impairment of the information on a domain, for instance, living things (animals) but the sparing of nonliving things (tools), or vice versa. Despite the large number of studies purportedly documenting double dissociations between both domains, the lack of theoretical debate on how to empirically define such dissociations is unclear, e.g. how they should be evaluated and reported. Development. In this work, a review of literature on category-specific and the explanatory models is showed. A critical methodological is done, on the basis of three findings: 1) lack of normal control groups in the majority of case studies; 2) the questionable utilization of double dissociations; and 3) the presence of problems due to a ‘ceiling effect’ in most group studies of Alzheimer disease patients. Conclusions. It is claimed that while domain specificity may be a legitimate phenomenon, the critical review of literature do not provide a strong empirical foundation for the domain fractionations claimed in this literature

A longitudinal analysis of memory in patients with schizophrenia.

Memory deficits are widely reported in patients with schizophrenia, but uncertainties remain about the extent and the longitudinal course of these deficits. Twenty-eight patients with a DSM-IV diagnosis of schizophrenia were tested on multiple aspects of memory at baseline, 9- and 18-month follow-up. Measures included: digit span, the Rivermead Behavioural Memory test (RBMT) battery, the Graded Naming Test (GNT) and several computerized memory tests from the Cambridge Automated Neuropsychological Testing Battery (CANTAB). A group of healthy controls (N=17) was tested on the CANTAB battery at baseline and 9-month follow up. The patients performed significantly poorer than controls on all CANTAB measures; however, there was no difference in change between groups over a 9-month period. Within-group patient comparisons revealed that symptoms reduced significantly over the study period, but had no association with memory. Significant improvements were observed for patients on two verbal memory tasks: the GNT and digit span, but not on any other measure. Interestingly, these were the only two tests on which patients were within normal limits at baseline. This study shows that patients with schizophrenia have deficits in multiple aspects of memory which remain stable over long periods of time. In addition, patients showed a tendency to improve on memory tasks which contained a verbal component.

Hypofrontality in schizophrenia: a meta-analysis of functional imaging studies.

OBJECTIVE: Hypofrontality is not a well-replicated finding in schizophrenia either at rest or under conditions of task activation. METHOD: Studies comparing whole brain and frontal blood flow/metabolism in schizophrenic patients and normal controls were pooled. Voxel-based studies were also combined to examine the pattern of prefrontal activation in schizophrenia. RESULTS: Whole brain flow/metabolism was reduced in schizophrenia to only a small extent. Resting and activation frontal flow/metabolism were both reduced with a medium effect size. Duration of illness significantly moderated resting hypofrontality, but the moderating effects of neuroleptic treatment were consistent with an influence on global flow/metabolism only. Pooling of voxel-based studies did not suggest an abnormal pattern of activation in schizophrenia. CONCLUSION: Meta-analysis supports resting hypofrontality in schizophrenia. Task-activated hypofrontality is also supported, but there is little from voxel-based studies to suggest that this is associated with an altered pattern of regional functional architecture.

Category-specific naming errors in normal subjects: the influence of evolution and experience.

The importance of "artifactual" variables (such as conceptual familiarity) have been highlighted in current accounts of category-specific disorders for living things (e.g., Funnell & Sheridan, 1992). The difficulties experienced by patients are essentially viewed as an exaggeration of normal processes and the implication is that normal subjects should also have greater difficulty naming living items (because they have lower conceptual familiarity than nonliving things). The current study examined normal subjects' ability to name pictures of artifact-matched sets of living and nonliving things in a naming-to-deadline paradigm. Contrary to the prediction, normal subjects made more nonliving naming errors. Furthermore, female subjects made more nonliving-thing errors than male subjects. These findings could not be reduced to differences in either category-based or gender-based familiarity ratings. Rather, it is proposed that an elaborated domain-specific evolutionary model parsimoniously explains both the greater incidence of living thing deficits in patients and the better performance of normal subjects with living things.

Lexical knowledge degradation in schizophrenia.

This study documents a severe picture naming impairment in a series of 22 chronically hospitalised schizophrenics. The pattern and level of naming impairment were comparable in degree and type to that seen neurological patients with left hemisphere lesions. This deficit was further examined to determine whether it conformed to a disorder affecting access to the lexical representations or some degradation of the stored representations themselves. Patient naming was examined twice (18months apart) for evidence of consistency and for word frequency effects. The pattern of individual patient performance on these criteria showed that the majority had storage disorders; access disorders alone occurred in only a small minority of patients. A subset of 11 of the same patients that were tested on three occasions (across 30months) showed the same pattern but further indicated that when access problems are present, they reflect difficulty with deliberate, rather than automatic, access to the lexicon.

Loss of stored knowledge of object structure: implications for "category-specific" deficits.

Following a right-hemisphere lesion, the patient SM had impaired object recognition, with good elementary visual abilities, and could derive information about object structure. He was also impaired on all tasks tapping stored structural knowledge, even when tested in the verbal modality. This suggests that SM has a disorder affecting stored knowledge of object structure, though he remains able to assemble novel structural descriptions. His object recognition ability also appeared significantly worse for non-living things. By contrast, existing models relating to stored knowledge would predict that SM would show greater impairment with living things. We argue that SM's deficit reflects the loss of a type of structural knowledge that relates to the "within-item structural diversity" of items. It is argued that living things show less structural variation than objects in the natural world, and might arguably be easier to recognise, because the image of the to-be-recognised object would be similar to the stored representation. Hence, a deficit affecting this aspect of stored knowledge would differentially impact upon non-living things. This argument receives confirming independent support from the finding that normal subjects ratings for the within-item structural diversity of visual stimuli are (unlike other "critical" variables) significant predictors of SM's naming performance.