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Schizophrenia is a psychiatric diagnosis where there is high variation among patients in age at onset, symptoms, treatment response and other factors. There have been attempts to classify different types of schizophrenics by symptoms to improve diagnostic accuracy; one such attempt resulted in the deficit and nondeficit distinction. Deficit symptoms are thought to arise from physiological disease processes that weaken emotional activities involved in volition (making choices). These people are thought to have more negative symptoms that result from an increased degree of neurological impairment or brain pathology. The validity of these hypotheses regarding deficit schizophrenic patients was tested. Thirty-four patients were divided into two groups of 17 with a diagnosis of deficit or nondeficit schizophrenia. This distinction required differentiating between primary, enduring negative symptoms and transient secondary negative symptoms. Each patient was then evaluated for premorbid adjustment and degree of neurological impairment. The premorbid adjustment evaluation assessed social, scholastic, and sexual development at four age periods. They found that in the deficit group, premorbid adjustment was significantly worse in childhood and adolescence, and overall, than the nondeficit group. The deficit group was more impaired on each item from each age group evaluated. The deficit patients were also more neurologically impaired than the nondeficit patients, with significant differences measured on four out of five items tested. These differences were in the area of sensory integration, with no differences revealed in motor coordination. This might indicate neurological dysfunction in the parietal cortex of the brain, which has been suggested by earlier studies. The authors feel that these results support the validity of subgrouping schizophrenics in this way. They suggest that the deficit patients are characterized by a disease process with an onset before adolescence. (Consumer Summary produced by Reliance Medical Information, Inc.)

When speaking of the symptomatology of mental illness, a distinction is made between what are termed positive symptoms, such as delusions and hallucinations, and negative symptoms, such as emotional deficits and thought disorders. In studying social dysfunction among schizophrenics, opinions differ as to whether its roots lie in negative, positive, or a mixture of both types of symptoms. To further clarify this issue, 151 schizophrenic subjects and their twins were analyzed for the presence of negative and positive symptoms. Significant differences between positive and negative symptoms were not found between male and female schizophrenic subjects. Schizophrenic men had significantly more social problems both before and after onset of their illness than schizophrenic women. Because this was not associated with more negative symptoms, it suggests that disordered social relationships result from separate functional processes in the development of schizophrenia. Based on these findings, the authors suggest that social functioning in schizophrenics should be examined separately from negative symptoms, and not simply included as one component of negative symptomatology. (Consumer Summary produced by Reliance Medical Information, Inc.)

Objective: The authors have previously shown the role of depression, slowing of processing speed, and selective attention deficit in verbal memory task performance in schizophrenia. They wished to determine the specific contribution of each of these factors to various types of memory impairment. Method: The negative symptom score from the Positive and Negative Syndrome Scale, the Hamilton Depression Rating Scale score, a measure of processing speed, and a measure of selective attention were entered as predictors in regression analyses. Furthermore, analyses of covariance were conducted on the memory measures to test the significance of the differences between schizophrenic patients and healthy comparison subjects after control for processing speed and selective attention. Results: Depression was associated only with deep encoding reflected by semantic clustering. Selective attention was associated only with superficial encoding reflected by serial recall. Slowing of processing speed was associated with both deep and superficial encoding. Negative symptoms were not associated with memory impairment except for the avolition item from the Scale for the Assessment of Negative Symptoms. Processing speed accounted for all the group differences on the memory measures that reflected superficial encoding. In addition, a subgroup of patients with no or minor depression was not significantly impaired on deep encoding relative to the healthy comparison group. Conclusions: The authors suggest that verbal memory impairment in schizophrenia is a consequence of depression and slowness, rather than a primary feature of the disease. (Am J Psychiatry 2001; 158:758-764)

Objective: The biological characteristics of schizophrenia are often studied by using functional imaging techniques. However, since volunteers with schizophrenia routinely fail to perform as accurately or as quickly as healthy volunteers, it is difficult to ascertain whether a particular deficit in blood flow to a brain region is due to behavior or to the underlying illness. In this report, investigators used an auditory recognition task to assess brain blood flow patterns and behavioral correlates of schizophrenic patient volunteers trained on the task. Method: Twelve healthy volunteers and 18 volunteers with schizophrenia were trained to make tone frequency recognitions. Accuracy and stimuli were matched between groups. Participants were required to press a button to indicate whether a briefly presented tone was the high-frequency (1500 Hz) reference tone or one of a lower frequency level (level chosen to elicit an 80% accuracy score). Subjects underwent bolus [[sup.15]O][H.sub.2]O blood flow positron emission tomography during inactive rest, a sensory motor control condition, and the decision task. Blood flow patterns were assessed between conditions and between groups. Results: As a group, the patients with schizophrenia (who performed as quickly and accurately as the comparison subjects) exhibited significantly less change in regional cerebral blood flow (rCBF) to the anterior cingulate and supplementary motor cortices when switching from the sensory motor control to the decision condition. There were also marked between-group differences in correlations between rCBF and response time. Whereas the comparison subjects exhibited progressively greater blood flow to the frontal cortex in association with longer response times, the schizophrenic patients exhibited progressively lower blood flow in conjunction with extended response times. Conclusions: The failure to appropriately enhance cingulate activity when engaged in a demanding task and the progressive, time-dependent decline in frontal blood flow suggest that patients with schizophrenia are unable to make optimal use of frontocingulate systems when maximally engaged in high-error tasks. (Am J Psychiatry 2000; 157:1634-1645)