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.
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.
Sex differences in neurocognitive abilities have been extensively explored both in the healthy population and in many disorders. Until recently, however, little work has examined such differences in people with Alzheimer's disease (AD). This is despite clear evidence that AD is more prevalent in women, and converging lines of evidence from brain imaging, post-mortem analyses, hormone therapy and genetics suggesting that AD affects men and women differently. We provide an overview of evidence attesting to the poorer cognitive profiles in women than in men at the same stage of AD. Indeed, men significantly outperform women in several cognitive domains, including: Language and semantic abilities, visuospatial abilities and episodic memory. These differences do not appear to be attributable to any differences in age, education, or dementia severity. Reasons posited for this female disadvantage include a reduction of estrogen in postmenopausal women, greater cognitive reserve in men, and the influence of the apolipoprotein E ε4 allele. Assessment of cognitive abilities contributes to the diagnosis of the condition and thus, it is crucial to identify the role of sex differences if potentially more accurate diagnoses and treatments are to emerge.
Studies reporting on the cognitive abilities of men and women with Alzheimer's disease (AD) are surprisingly rare. We carried out a meta-analysis of neurocognitive data from 15 studies (n = 828 men; 1,238 women), which revealed a consistent male advantage on verbal and visuospatial tasks and tests of episodic and semantic memory. Moderator regression analyses showed that age, education level, and dementia severity did not significantly predict the male advantage. Reasons posited for this advantage include a reduction of estrogen in postmenopausal women, sex differences in AD pathology, and greater cognitive reserve in men.
Objective The current meta-analysis examines the effects of ketamine infusion on depressive symptoms over time in major depressive disorder (MDD) and bipolar disorder (BD). Methods Following a systematic review of the literature, data were extracted from 21 studies (n = 437 receiving ketamine) and analysed at four post-infusion time points (4 h, 24 h, 7 days and 12-14 days). The moderating effects of several factors were assessed including: repeat/single infusion, diagnosis, open-label/participant-blind infusion, pre-post/placebo-controlled design and the sex of patients. Results Effect sizes were significantly larger for repeat than single infusion at 4 h, 24 h and 7 days. For single infusion studies, effect sizes were large and significant at 4 h, 24 h and 7 days. The percentage of males was a predictor of antidepressant response at 7 days. Effect sizes for open-label and participant-blind infusions were not significantly different at any time point. Conclusions Single ketamine infusions elicit a significant antidepressant effect from 4 h to 7 days; the small number of studies at 12-14 days post infusion failed to reach significance. Results suggest a discrepancy in peak response time depending upon primary diagnosis -24 h for MDD and 7 days for BD. The majority of published studies have used pre-post comparison; further placebo-controlled studies would help to clarify the effect of ketamine over time.
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. Key words : Bipolar disorder, cognitive therapy, depression, schizophrenia. IntroductionCognitive behavioural therapy (CBT) has been widely adopted by psychiatry in recent years, but its increase in use in the severe disorders of schizophrenia, major depression and bipolar disorder is particularly noteworthy. This is because it challenges what has, until recently, been a dominance of biological approaches to these disorders. Thus, although contemporary accounts of schizophrenia (e.g. Picchioni & Murray, 2007) emphasize biological factors in its aetiology and consider neuroleptic drugs to be the mainstay of treatment, official UK treatment guidelines from the National Institute for Clinical Excellence (NICE) also state that psychological interventions are indispensable and that CBT should be offered to all patients (NICE, 2003(NICE, , 2009. Psychological factors may loom larger in the aetiology of major affective disorder, but when it comes to treatment, the emphasis in the literature, particularly in bipolar disorder, has once again been firmly on pharmacotherapy. Attitudes may be changing here too, however. References to the effectiveness of CBT are pervasive in the UK depression treatment guideline (NICE, 2004) ; a government initiative is under way in the UK to provide CBT for depression and anxiety in 250 dedicated therapy centres (Layard, 2006) ; and CBT is being advocated for relapse prevention in bipolar disorder (e.g. Scott & Colom, 2005 ;Basco & Rush, 2007).Nevertheless, a cursory look at the literature reveals well-conducted trials where CBT has had negative findings in all three disorders. For example, large-scale trials of CBT in schizophrenia have failed to find significant advantages over befriending (Sensky et al. 2000) or supportive counselling (L...
A majority of studies show that schizophrenics perform poorly on so-called tests of executive or frontal lobe function--the paradigmatic case being the Wisconsin Card Sort Test (WCST). Nevertheless, the specific character of this deficit in schizophrenia remains underspecified. In particular, it seems premature to assume that schizophrenia is characterised by an executive dysfunction and/or a disorder of frontal lobe function before determining whether any deficit is: selective; disproportionate to the general level of intellectual functioning; or qualitatively comparable with that of frontal lobe patients. A meta-analysis was conducted on 29 studies comparing the performance of schizophrenics and normal controls on the WCST. This showed that the mean weighted effect size was large for categories achieved (d = 0.91), medium for absolute level of perseveration (d = 0.53), but only small for the proportion of perseverative errors (d = 0.18). By contrast, the effect size for Wechsler Adult Intelligence Scale Intelligence Quotient (WAIS IQ) in a subset of these studies (d = 1.23) was significantly larger than for any WCST measures. This pattern of findings challenges notions that schizophrenia is characterised by an executive dysfunction that is: selective; disproportionate to IQ level; and analogous to that found in frontal lobe patients. Rather, the poor WCST performance of schizophrenics appears to reflect a generalised intellectual deficit.
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.
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