Negative symptoms and hypofrontality in chronic schizophrenia.

Frontal lobe dysfunction is widely suspected to underlie negative symptoms of schizophrenia. This hypothesis is based largely on long-standing observations of the similarities between the effects of frontal lobe lesions and negative symptoms. However, there is little direct evidence specifically for such an association in schizophrenic patients. We measured the relationship between decreased relative prefrontal cortex glucose metabolism (hypofrontality) using positron emission tomography and evaluated the severity of negative symptoms in 20 chronic schizophrenics who underwent scanning while not receiving neuroleptic drugs. We found a close relationship between negative symptoms and prefrontal hypometabolism, particularly in the right dorsolateral convexity. This association was regionally specific. Furthermore, there was no evidence that this relationship was an artifact of age, cerebral atrophy, or severity of positive symptoms.     

Negative priming in schizophrenia revisited

Reduced spatial negative priming (SNP) in schizophrenia is commonly attributed to the inability to filter out irrelevant information. However, some investigators have suggested that reduced SNP in patients is caused by either perceptual mismatching or salience of the distracter. The goal of the present study was to determine the influence of these perceptual processes. In this preliminary report, we present data of 15 schizophrenia patients on atypical medication and 15 matched healthy controls. Compared to controls, patients showed a reduced SNP effect, even when controlled for perceptual mismatching. This reduced effect was not affected by distracter salience.     

Negative symptoms and emotions in schizophrenia

A 32-year-old man, who has suffered from schizophrenia for 12 years, has been rated by five professionals using the Scale for the Assessment of Negative Symptoms. These ratings are compared with samples of the patient's writing, which reflect his emotions. The results suggest that a patient exhibiting moderate negative symptoms may be experiencing feelings that he does not display through either verbal or facial expression.     

Negative parkinsonian, depressive and catatonic symptoms in schizophrenia: a conflict of paradigms revisited

Background: To study the interrelationship pattern of negative, depressive, parkinsonian and catatonic symptoms over an exacerbation phase of schizophrenia. Method: Forty-five inpatients with a DSM-IV diagnosis of schizophrenia or schizophreniform disorder were assessed at admission and discharge for negative, depressive, parkinsonian and catatonic symptoms. A subsample of patients unmedicated at admission (n=23) was specifically analyzed. Results: Negative, parkinsonian and catatonic symptoms correlated significantly at both assessment points, as did their mean changes over the episode. At admission, depressive symptoms did not correlate with negative, parkinsonian or catatonic symptoms, but they did at discharge. Changes of depressive symptoms over the episode did not correlate with changes of the other groups of symptoms. In the patients who were unmedicated at admission, ratings of non-akinetic parkinsonism, unlike ratings of akinetic parkinsonism, worsened significantly after neuroleptic treatment. Conclusions: While negative, parkinsonian and catatonic symptoms are highly related features, depressive symptoms seem to be a relatively independent dimension of psychopathology in schizophrenia. Non-akinetic parkinsonian symptoms may be more useful than the akinetic symptoms in distinguishing primary from drug-induced negative symptoms.     

Negative symptoms and the early course of schizophrenia.

To determine the usefulness of including a duration criterion in the definition of "negative" symptoms, the prognostic significance of a longitudinally obtained measure of negative symptoms was compared with a cross-sectionally obtained measure. As predicted, the presence of negative symptoms based on longitudinal observation was associated with most aspects of 18-month course in a group of "first-episode" schizophrenic individuals, whereas cross-sectional levels of negative symptoms were not. The findings suggest that negative symptoms, when operationalized as a trait-like phenomenon, help to portend a poor course of illness.     

Negative symptoms in schizophrenia: a review

Negative symptoms refer to the weakening or lack of normal thoughts, emotions or behaviour in schizophrenia patients. Their prevalence in first-episode psychosis is high, 50-90%, and 20-40% of schizophrenia patients have persisting negative symptoms. Severe negative symptoms during the early stages of treatment predict poor prognosis. The aim of the study was to review the current literature on the negative symptoms of schizophrenia. In June 2007, the following databases were searched: Web of Science, PubMed, PsycINFO, Medline (Ovid) and Scopus. The search included articles written in English and no time limit was determined. The studies were manually screened by one of the authors according to the title and abstract. About one in three schizophrenia patients suffer from significant negative symptoms. In these patients, negative symptoms constitute a key element of overall symptoms, weakening their ability to cope with everyday activities, affecting their quality of life and their ability to manage without significant outside help. About one in three schizophrenia patients suffer from significant negative symptoms. Attention should be focused on negative symptoms during the early phase of treatment, because they cause significant impairment to patients' quality of life. So far, no treatment appears to substantially improve negative symptoms narrowly defined. However, according to clinical experience, when treating negative symptoms, the best effect is achieved by optimizing the dose of medication and by complementing it with psychosocial therapies.     

Negative symptoms and reaction time in schizophrenia

This study explored the association of negative symptoms and reaction time. Negative symptoms were specifically associated with reaction time slowing and variability in schizophrenics, but not in affective disorders. The finding of specificity did not extend to other measures of the deficit syndrome nor to motor performance. An abbreviated version of the negative symptom scale was especially effective in separating groups.     

Negative symptoms and neuroleptics in catatonic schizophrenia

The association between neuroleptic treatment and the negative symptom dimension (ND) was evaluated in 1528 schizophrenia patients. In patients receiving more than 820 mg chlorpromazine (CPZ), those with catatonic-type disorder had significantly (p<0.05) higher ND scores than those in any of the other diagnostic subtypes. Even in patients receiving 450 mg CPZ or more, catatonic patients had significantly (p=0.046) higher ND scores than other patients. Patients with catatonic schizophrenia are highly vulnerable to negative symptoms related to neuroleptic drugs, probably because of a defect in their dopaminergic neuronal pathways.     

Negative symptoms and social skills performance in schizophrenia

The present study aimed to determine whether the negative symptoms of patients with schizophrenia were better predictors of social competence than a range of other variables pertaining to demographics, illness, hospitalization, and premorbid functioning. Independent raters assessed social skills performance on a video-taped role-play test and 5 min conversation in 53 inpatients with a DSM-III diagnosis of schizophrenia. Patients' social skills were also assessed by ward nurses. Project clinicians assessed depression, medication side effects and positive and negative symptoms. Multiple-regression analyses demonstrated that, generally, negative symptoms were the best predictors of social skills performance.     

Negative symptoms in schizophrenia: neurobiological models and treatment response.

Evidence from lesioning studies and neuroimaging has linked negative symptoms to dysfunction of the prefrontal cortex, the limbic system, and the basal ganglia. Although such symptoms have been most strongly associated with dopaminergic hypoactivity in the prefrontal cortex, other neurotransmitters including norepinephrine, serotonin, and the excitatory amino acids may also play a role. In some patients moderate doses of conventional neuroleptics clearly improve negative symptoms; the response of such symptoms is relatively greater with clozapine and probably with certain serotonin-dopamine antagonists. Recent studies demonstrating improvement of negative symptoms when conventional neuroleptics are augmented with selective serotonin-reuptake inhibitors or with agents active at the glycine-modulatory site of the glutamatergic N-methyl-D-aspartate receptor complex suggest that further amelioration of primary negative symptoms may be possible through pharmacological strategies involving multiple neurotransmitter systems.     

Negative symptoms in schizophrenia and nailfold plexus visibility

Visibility of the nailfold vascular plexus has shown promise as a genetically transmitted marker for liability to schizophrenia. To assess whether this marker is specifically associated with negative or positive symptoms of schizophrenia, we reanalyzed patient data collected 20 years ago, well before interest in the negative/positive symptom distinction. Eighty-four patients, who retrospectively met DSM-III-R criteria for schizophrenia, had been rated for plexus visualization score (PVS) and independently interviewed using the Mental Status Schedule (MSS). Content scales were derived from the MSS to assess negative, positive, and affective symptoms. There was a highly significant correlation between PVS and negative symptoms (including verbal, motor, cognitive and motivational deficits), but not between PVS and positive or affective symptoms. These findings indicate that the negative symptoms of schizophrenia are due to a disease process biologically distinguishable from those causing positive symptoms and that plexus visibility is a risk marker for this pathology.     

Negative symptoms in chronic non-schizophrenic patients

Negative symptoms are mostly associated with schizophrenic illness. This paper discusses the presence of negative symptoms in other chronic psychiatric illnesses. We have observed that longitudinally primary negative symptoms tend to be constant and are precisely symptoms which can define chronicity. They are as unspecific as positive symptoms in mental illness.     

Negative symptoms of schizophrenia and compliance with medication

Poor compliance with medication has been reported in up to 40 percent of outpatients with schizophrenia. This study examines the relationship between compliance with depot neuroleptic medication and severity of negative symptoms of schizophrenia. Compliance with depot neuroleptic medication during the preceding year was calculated for 64 patients with a DSM-III-R diagnosis of schizophrenia. The severity of negative symptoms was assessed using the Scale for the Assessment of Negative Symptoms (SANS). Patients who complied poorly with medication had significantly greater severity of negative symptoms of schizophrenia, especially avolition, apathy, and alogia. Duration of illness and duration of prescribed medication were independently associated with compliance, but no other features were associated in the multiple regression model. These findings suggest that negative symptoms are one of the factors of importance in determining whether a patient will attend for depot neuroleptic medication.     

Dysphoric and depressive symptoms in chronic schizophrenia

This study suggests that depressive symptoms are less common in severe, chronic, schizophrenic inpatients than would be predicted if these symptoms were manifestations of negative symptoms or drug-induced parkinsonism. The findings further suggest that depressive symptoms in such patients are independent phenomena which conform to a depressive syndrome. This depression does not represent a misidentification of the negative symptoms affective flattening and alogia, as measured by the SANS, or parkinsonism or akathisia. The study findings fail to support the view that long-term depot antipsychotic medication plays an important role in the genesis of depression and dysphoria in chronic schizophrenic patients. Depressive symptoms were found to occur as frequently, and dysphoria more frequently, in schizophrenic patients in the year after drug withdrawal compared with patients continuing on maintenance drug treatment for the same period.