Co-administration of atypical antipsychotics and antidepressants disturbs contrast detection in schizophrenia

Is Schizophrenia a Disorder of Consciousness? Experimental and Phenomenological Support for Anomalous Unconscious Processing

Decades ago, several authors have proposed that disorders in automatic processing lead to intrusive symptoms or abnormal contents in the consciousness of people with schizophrenia. However, since then, studies have mainly highlighted difficulties in patients' conscious experiencing and processing but rarely explored how unconscious and conscious mechanisms may interact in producing this experience. We report three lines of research, focusing on the processing of spatial frequencies, unpleasant information, and time-event structure that suggest that impairments occur at both the unconscious and conscious level. We argue that focusing on unconscious, physiological and automatic processing of information in patients, while contrasting that processing with conscious processing, is a first required step before understanding how distortions or other impairments emerge at the conscious level. We then indicate that the phenomenological tradition of psychiatry supports a similar claim and provides a theoretical framework helping to understand the relationship between the impairments and clinical symptoms. We base our argument on the presence of disorders in the minimal self in patients with schizophrenia. The minimal self is tacit and non-verbal and refers to the sense of bodily presence. We argue this sense is shaped by unconscious processes, whose alteration may thus affect the feeling of being a unique individual. This justifies a focus on unconscious mechanisms and a distinction from those associated with consciousness.

Schizophrenia and the eye

Although visual processing impairments are common in schizophrenia, it is not clear to what extent these originate in the eye vs. the brain. This review highlights potential contributions, from the retina and other structures of the eye, to visual processing impairments in schizophrenia and high-risk states. A second goal is to evaluate the status of retinal abnormalities as biomarkers for schizophrenia. The review was motivated by known retinal changes in other disorders (e.g., Parkinson’s disease, multiple sclerosis), and their relationships to perceptual and cognitive impairments, and disease progression therein. The evidence reviewed suggests two major conclusions. One is that there are multiple structural and functional disturbances of the eye in schizophrenia, all of which could be factors in the visual disturbances of patients. These include retinal venule widening, retinal nerve fiber layer thinning, dopaminergic abnormalities, abnormal ouput of retinal cells as measured by electroretinography (ERG), maculopathies and retinopathies, cataracts, poor acuity, and strabismus. Some of these are likely to be illness-related, whereas others may be due to medication or comorbid conditions. The second conclusion is that certain retinal findings can serve as biomarkers of neural pathology, and disease progression, in schizophrenia. The strongest evidence for this to date involves findings of widened retinal venules, thinning of the retinal nerve fiber layer, and abnormal ERG amplitudes. These data suggest that a greater understanding of the contribution of retinal and other ocular pathology to the visual and cognitive disturbances of schizophrenia is warranted, and that retinal changes have untapped clinical utility.

Antidepressants for people with both schizophrenia and depression

BACKGROUND

Depressive symptoms, often of substantial severity, are found in 50% of newly diagnosed suffers of schizophrenia and 33% of people with chronic schizophrenia who have relapsed. Depression is associated with dysphoria, disability, reduction of motivation to accomplish tasks and the activities of daily living, an increased duration of illness and more frequent relapses.

OBJECTIVES

To determine the clinical effects of antidepressant medication for the treatment of depression in people who also suffer with schizophrenia.

SEARCH STRATEGY

We undertook electronic searches of the Cochrane Schizophrenia Group's Register (October 2000), ClinPsych (1988-2000), The Cochrane Library (Issue 3, 2000), EMBASE (1980-2000) and MEDLINE (1966-2000). This was supplemented by citation searching, personal contact with authors and pharmaceutical companies.

SELECTION CRITERIA

All randomised clinical trials that compared antidepressant medication with placebo for people with schizophrenia or schizoaffective disorder who were also suffering from depression.

DATA COLLECTION AND ANALYSIS

Data were independently selected and extracted. For homogeneous dichotomous data the fixed effects risk difference (RD), the 95% confidence intervals (CI) and, where appropriate, the number needed to treat (NNT) were calculated on an intention-to-treat basis. For continuous data, reviewers calculated weighted mean differences. Statistical tests for heterogeneity were also undertaken.

MAIN RESULTS

Eleven studies met the inclusion criteria. All were small, and randomised fewer than 30 people to each group. Most included people after the most acute phase of psychosis and investigated a wide range of antidepressants. The quality of reporting varied a great deal. For the outcome of 'no important clinical response' antidepressants were significantly better than placebo (n=209, 5 RCTs, summary risk difference fixed effects -0.26, 95% CI -0.39 to -0.13, NNT 4 95% CI 3 to 8). The depression score at the end of the trial, as assessed by the Hamilton Rating Scale (HAM-D), seemed to suggest that using antidepressants was beneficial, but this was only statistically significant when a fixed effects model was used (n=261, 6 RCTs, WMD fixed effects -2.2 95% CI -3.8 to -0.6; WMD random effects -2.1 95% CI -5.04 to 0.84). There was no evidence that antidepressant treatment led to a deterioration of psychotic symptoms in the included trials. Heterogeneous data on 'any adverse effect' are equivocal (n=110, 2 RCTs, RD fixed 0.11 CI -0.03 to 0.25, Chi square 7.5, df=1, p=0.0062). In one small study extrapyramidal adverse effects were reported less often by those allocated to antidepressant (n=52, 1 RCT, RD fixed -0.28 CI -0.5 to -0.04). Only about 10% of people left these studies by 12 weeks. There was no apparent difference between those allocated placebo and those given an antidepressant (n=426, 10 RCTs, RD fixed 0.04 CI -0.02 to 0.1).

REVIEWER'S CONCLUSIONS

Overall, the literature was of poor quality, and only a small number of trials made useful contributions. Though our results provide some evidence to indicate that antidepressants may be beneficial for people with depression and schizophrenia, the results, at best, are likely to overestimate the treatment effect, and, at worst, could merely reflect selective reporting of statistically significant results and publication bias. At present, there is no convincing evidence to support or refute the use of antidepressants in treating depression in people with schizophrenia. We need further well-designed, conducted and reported research to determine the best approach towards treating depression in people with schizophrenia.