Manuel J. Cuesta

Psychometric Properties of the Positive and Negative Syndrome Scale (PANSS) in Schizophrenia

We analyzed the psychometric properties of the Positive and Negative Syndrome Scale (PANSS) in a sample of 100 DSM-III-R schizophrenic patients. Our findings coincided with the results of Kays group in the following points: (1) the PANSS scores were normally distributed; (2) the positive and negative scales showed good interrater reliability; (3) positive and negative syndromes are independent constructs; (4) the positive and negative scales held a high concurrent validity in relation to the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms; and (5) although positive and negative syndromes showed factorial validity, they were not sufficient to account for the whole of the schizophrenic symptoms. Unlike Kays group, we found a modest internal consistency of the positive scale, indicating that it is composed of several independent components. The data suggest that the distinction between positive and negative symptoms is an oversimplification, and that schizophrenic symptoms can be better conceptualized as composed of, at least three dimensional syndromes: positive, disorganized, and negative.

How many and which are the psychopathological dimensions in schizophrenia? Issues influencing their ascertainment

During the last two decades, much effort has been made to precisely characterize the symptom dimensions of schizophrenia. A number of dimensional models have been proposed, the most popular of which has been a three-dimensional model consisting of psychotic, negative and disorganizational symptoms. This model, however, has been criticized as too simplistic, and more complex models have been proposed, although to date there has been no consensus as to the number and nature of dimensions necessary to account for the whole range of schizophrenic symptoms. In the present paper, the authors review the main methodological issues which have led to the current confusion about the number of dimensions underlying schizophrenic psychopathology. Among the main issues influencing the delimitation of dimensions are: statistical procedures for determining the number of factors, phase of the illness, level of analysis of symptoms (i.e., symptoms or groups of symptoms), and measurement instrument used. Studies analyzing either a broad range of symptoms or particular symptoms at a finer level have produced a rather complex picture of schizophrenic dimensions. There is evidence supporting the existence of eight major dimensions of psychopathology: psychosis, disorganization, negative, mania, depression, excitement, catatonia and lack of insight. The dimensional structure of symptoms becomes even more complex if one considers that these big dimensions can be further divided into more elementary components. A hierarchical approach for organizing the complex dimensional structure of schizophrenic symptoms is proposed.

Effects of olanzapine and other antipsychotics on cognitive function in chronic schizophrenia: a longitudinal study

This study aimed to determine the effect of olanzapine and other antipsychotic drugs on cognitive functions after 6months of treatment. Baseline, 3month and 6month psychopathological and cognitive evaluations were made. Thirty-eight partially responsive outpatients with DSM-IV chronic schizophrenia diagnosis were included in the study. On the indication of their attending psychiatrists, 21 patients initiated treatment with olanzapine, and 17 remained on their previous treatment with other antipsychotic drugs. Cognitive assessments were blind to medication and psychopathological status. The olanzapine group presented a significantly greater improvement in negative symptomatology and verbal memory than the comparison group in repeated-measures of MANOVAs between baseline, 3month and 6month assessments. These differences remained statistically significant after covarying out gender, treatment with other atypical antipsychotics, biperidene doses and changes in positive and negative symptoms. In order to match previous differences between groups, cognitive baseline scores for each test were introduced as covariates, resulting in a significant improvement for the olanzapine group in negative symptomatology and the interference task of the Stroop test.We then re-analyzed the data, dividing the comparison group into two groups: risperidone-treated patients (n=9) and patients receiving conventional antipsychotic drugs (n=8). Post-hoc analyses between groups were carried out with baseline cognitive assessment as covariate. The olanzapine group improved significantly more than the risperidone group in negative symptomatology and in the interference task of Stroop test. The improvement in the number of categories of the Wisconsin Card Sorting Test was higher in risperidone patients than in those receiving olanzapine or conventional antipsychotic treatment. Conventional antipsychotic drugs did not present a significant improvement over atypical antipsychotic drugs in any cognitive function. In summary, in patients suffering from chronic schizophrenia, atypical antipsychotic agents were associated with slight differential improvements over time in attentional, verbal memory and executive functions compared with conventional neuroleptic drugs. No differential improvements were found in social functioning, verbal fluency, non-verbal domains of memory or visuo-motor abilities.

Dimensional structure of psychotic symptoms: an item-level analysis of SAPS and SANS symptoms in psychotic disorders

The factor structure of psychotic symptoms as assessed by means of the Scales for the Assessment of Positive and Negative Symptoms (SAPS and SANS) was examined in a sample of 660 psychotic inpatients. Analyses were conducted at item-level. Principal-component analysis (PCA) was used to extract factors, the OBLIMIN procedure to rotate factors, and the eigen value greater-than-one criterion to determine the number of factors. PCA resulted in 11 interpretable factors explaining 64% of the total variance: poverty of affect/speech, thought disorder/inappropriate affect, bizarre delusions, social dysfunction, other delusions, paranoid delusions, bizarre behavior, nonauditory hallucinations, auditory hallucinations, manic thought disorder, and attention. Many of the factors were significantly intercorrelated. A second-order PCA resulted in four second-order factors, the first three roughly corresponding to the well-known psychosis, disorganization and negative dimensions. It is concluded that the factor structure of psychotic symptoms is more complex than is generally acknowledged, and that the dimensions of psychosis, disorganization and negative represent second-order dimensions. The subscale composition of the SAPS and SANS was not supported.

Influence of cannabis abuse on schizophrenic psychopathology.

A study was carried out on a group of 95 schizophrenic patients (DSM‐III‐R criteria) under the age of 35, 23 of whom were cannabis abusers in the past year. The objective of the study was to evaluate the effect of cannabis on positive and negative schizophrenic symptoms, evaluated using Andreasens Scales for the Assessment of Positive and Negative Symptoms (SAPS and SANS). There were no statistically significant differences between the groups on the SAPS; the group of cannabis abusers had higher scores except for the delusions subscale. On the SANS nonabusers scored higher, with a significant difference on the alogia subscale. The results suggest that the consumption of cannabis by schizophrenic patients could attenuate negative symptoms, which would support the self‐medication hypothesis of cannabis abuse.

Cognitive disorders in the positive, negative, and disorganization syndromes of schizophrenia

Recent factor-analytic studies have derived several trisyndromic models for schizophrenia, all based on the positive, negative, and disorganization syndromes. The goal of this study was to examine cognitive disorders in these three schizophrenic syndromes. The study group was composed of 40 schizophrenic patients consecutively admitted to the hospital due to a recrudescence of their symptomatology. They were selected on the basis of a semistructured interview, diagnosed with DSM-III-R criteria, and evaluated with scales for positive and negative symptoms. Their cognitive disorders were assessed with a battery of neuropsychological tests. The schizophrenic syndromes were weakly associated with cognitive performance through direct correlations and after correction for confounding variables. The disorganization and negative syndromes were more strongly associated with cognitive disturbances than was the positive syndrome, and both were associated with disturbances of visual-motor processes. Moreover, the disorganization syndrome was associated with disturbances in language and verbal memory and in time-controlled performance.

Lack of insight in mood disorders

BACKGROUND The studys aim was to examine insight in mood disorders in relation to type of mood episode, psychotic state, and insight change over the episode. METHODS Fifty four patients with a manic or major depressive episode were interviewed for insight assessment at admission and discharge. RESULTS At admission, mania patients had more severe insight impairment that depressive ones, depressive patients with psychosis had poorer insight than those without psychosis, and mania patients had poor insight irrespective of the presence of psychotic symptoms. At discharge some insight impairment was observed in mania. CONCLUSION Lack of insight was a prevalent condition in psychotic depression and mania. LIMITATIONS A global insight measure was used. Ratings of insight were not blind to the ratings of other symptoms. CLINICAL RELEVANCE Considering residual insight impairment in mania may be important to maximize compliance and to prevent relapse.

The Val66Met polymorphism of the brain-derived neurotrophic factor gene is associated with risk for psychosis: Evidence from a family-based association study

Schizophrenia (SZ) is a prevalent and severe mental disorder. One of the most favored hypotheses for the etiology of SZ is the neurodevelopmental hypothesis. Brain‐derived neurotrophic factor (BDNF), a member of the neurotrophin growth factor family, promotes the development, regeneration, and survival of neurons and has been linked to the neuropathology of SZ. The present study tested, in a sample of 94 nuclear families, the hypothesis that the BDNF gene Val66Met polymorphism is associated to SZ and its psychopathologic phenotype using a multidimensional symptom approach. Furthermore, considering a reported reduction of BDNF in the frontal cortex of patients with SZ, we studied the relationship between this polymorphism and prefrontal function. The transmission disequilibrium test (TDT) showed a preferential transmission of allele Val from heterozygous parents to the affected offspring (P = 0.002), suggesting a possible role of this gene in the vulnerability to SZ spectrum disorders. The findings remained essentially unchanged when the analysis was restricted to the subgroup of patients with SZ (P = 0.009) and when a multidimensional approach to the diagnosis was used. Quantitative transmission disequilibrium test (QTDT) analyses did not demonstrate a significant association between the prefrontal tests assessed (Wisconsin Card Sorting Test and Trail Making Test) and the transmission of the BDNF alleles. Our finding suggests that the investigated BDNF polymorphism plays an important role in the phenotype of psychosis, but not in the performance of tests of prefrontal cognitive functions analyzed in these patients.

Factor Structure of Symptoms in Functional Psychoses

Global ratings from the Scale for the Assessment of Positive Symptoms and Scale for the Assessment of Negative Symptoms were subjected to principal-component analysis (PCA) in 80 schizophrenia patients, 76 patients with schizophreniform disorder, 80 patients with schizoaffective and mood disorders, and 78 patients with delusional, brief reactive, and atypical psychoses. The resulting factors were correlated with depressive, manic, and catatonic syndromes, and subjected to a multivariate analysis of variance across DSM-III-R diagnoses. PCAs revealed that psychosis, disorganization, and negative factors were also present in each of the nonschizophrenic groups. The disorganization factor tended to be related to the manic syndrome, and the negative factor to depressive and catatonic syndromes. Overall, the three factors had little diagnostic relevance in functional psychoses, although the negative factor was relatively more characteristic of schizophrenia. The data suggest that positive, negative, and disorganization factors are not specific to schizophrenia; this is consistent with a dimensional view of psychopathology in functional psychoses.

Motor behavior abnormalities in drug‐naïve patients with schizophrenia spectrum disorders

Prevalence and correlates of primary motor abnormalities in schizophrenia are presently ill defined. This study was aimed at examining the prevalence, syndromic structure, external correlates, and response to antipsychotic medication of a broad array of primary motor abnormalities. Two‐hundred antipsychotic‐naive patients with schizophrenia spectrum disorders were examined for motor abnormalities using the Modified Rogers Scale. Thirty‐one motor signs were subjected to factor analysis, and the resulting factors examined for association with a number of risk factors, clinical and psychopathological variables. One‐hundred and eighty‐nine patients were reassessed for motor abnormalities after completing a 4‐week trial with antipsychotic medication. Prevalence rates for at least one motor sign and syndrome at baseline were 66% and 40%, respectively. Motor signs clustered together into seven clinically interpretable factors: abnormal involuntary movements, hypokinesia, retarded catatonia, echo‐phenomena, excited catatonia, catalepsy, and parkinsonism. All motor domains but parkinsonism were inter‐related. Abnormal involuntary movements were associated with variables indicating both neurodevelopmental dysfunction and illness severity, and most motor domains were closely related to negative or disorganization symptoms. Change scores in motor domains after treatment with antipsychotic medication indicated improvement for abnormal involuntary movements, hypokinesia, retarded catatonia, excited catatonia and echophenomena, and worsening for parkinsonism. It is concluded that primary motor dysfunction is a prevalent and heterogeneous condition of schizophrenia. Motor abnormalities segregate into various syndromes, which have different clinical correlates and a differential response pattern to antipsychotic medication. It is hypothesized that the existence of a differential dopaminergic dysfunction in the nigroestriatal circuitry is responsible for the generation of those motor domains that improve and worsen with antipsychotic drugs.