P50 in deficit and nondeficit schizophrenia

Journal of Psychiatry Neuroscience Jpn, 1998

Objective: To test the discriminant validity of a model predicting a dissociation between measures of right and left frontal lobe function in people with schizophrenia. Participants: Twenty-one clinically stable outpatients with schizophrenia. Interventions: Patients were administered the University of Pennsylvania Smell Identification Test (UPSIT), the Stroop Color-Word Test (Stroop), and the Positive and Negative Syndrome Scale (PANSS). Outcome measures: Scores on these tests and relation among scores. Results: There was a convergence of UPSIT and Stroop interference scores consistent with a common cerebral basis for limitations in olfactory identification and inhibition of distraction. There was also a divergence of UPSIT and Stroop reading scores suggesting that the olfactory identification limitation is distinct from a general limitation of attention or a dysfunction of the left dorsolateral prefrontal cortex. Most notable was the 81 % classification convergence between the UPSIT and Stroop incongruous colour naming scores compared with the near-random 57% classification convergence of the UPSIT and Stroop reading scores. Conclusions: These data are consistent with a right orbitofrontal dysfunction in a subgroup of patients with schizophrenia, although the involvement of mesial temporal structures in both tasks must be ruled out with further study. A multifactorial model depicting contributions from diverse cerebral structures is required to describe the pathophysiology of schizophrenia. Valid behavioural methods for classifying suspected subgroups of patients with particular cerebral dysfunction would be of value in the construction of this model. Objectif: Verifier la validite discriminante d'un modele predisant une dissociation entre des mesures de la fonction des lobes frontaux gauche et droit chez des personnes atteintes de schizophrenie. Participants: Vingt-et-un patients atteints de schizophrenie, stables et traites en service externe. Interventions: On a administre aux patients le test d'identification des odeurs de l'Universite de la Pennsylvanie (UPSIT), le test des mots et couleurs de Stroop (Stroop) et l'echelle des syndromes positifs et negatifs (PANSS). Mesures de resultats: Resultats obtenus a ces tests et relation entre les resultats. Resultats: On a constate, entre les resultats du test UPSIT et les resultats d'interference du test Stroop, une convergence conforme a une cause cerebrale commune de limitations de l'identification olfactive et de l'inhibition de la distraction. On a constate aussi une divergence entre les resultats du test UPSIT et les resultats de lecture du test Stroop qui indique que la limitation de l'identification olfactive est distincte d'une limita

Biological psychiatry, 1991

Schizophrenia Research, 2003

1991

Journal of Clinical and Experimental Neuropsychology, 2006

Deficits in odor identification and detection threshold sensitivity have been observed in schizophrenia but their relationship to clinical, cognitive, and biologic measures have not been clearly established. Our objectives were to examine the relationship between measures of odor identification and detection threshold sensitivity and clinical, neuropsychological, and anatomic brain measures. Twenty-one patients with schizophrenia and 20 healthy controls were administered psychophysical tests of odor identification and detection threshold sensitivity to phenyl ethyl alcohol. In addition, clinical symptom ratings, neuropsychological measures of frontal and temporal lobe function and whole brain MRIs were concurrently obtained. Patients exhibited significant deficits in odor identification but normal detection threshold sensitivity. Poorer odor identification scores were associated with longer duration of illness, increased negative and disorganized symptoms, and the deficit syndrome, as well as impairments in verbal and nonverbal memory. Better odor detection thresholds were specifically associated with first-rank or productive symptoms. Larger left temporal lobe volumes with MRI were associated with better odor identification in controls but not in patients. Given the relevance of the neural substrate, and the evidence of performance deficits, psychophysical probes of the integrity of the olfactory system hold special promise for illuminating aspects of the neurobiology underlying schizophrenia.

Schizophrenia Research, 1993

American Journal of Psychiatry, 2000

Schizophrenia Research, 1994

Forty-seven schizophrenic patients and 36 normal controls, matched for smoking history, were administered the University of Pennsylvania Smell Identification Test (UPSIT) and the Picture Identification Test (PIT). Amongst subjects successfully completing the PIT, non-smoking schizophrenic patients had significantly lower UPSIT scores than non-smoking controls. Smoking history and diagnosis did not interact to produce any pronounced effect. No significant gender difference was found. These results suggest schizophrenics display decreased olfactory identification even if likely confounders are adequately controlled.

Psychiatry Research, 2006

Negative affect plays a crucial role in the psychopathology of schizophrenia. Although it is known that negative emotion has a strong effect on cognitive performance, this interaction has mainly been studied in healthy volunteers. Hence, working memory was assessed in 24 schizophrenia patients and 24 matched comparison subjects with a 0-back/2-back continuous performance test. Simultaneously, negative emotion was induced by olfactory stimulation. Although subjective ratings confirmed that stimulation with a negative odor was associated with a significant increase in negative affect in patients and healthy volunteers, working memory performance was affected differentially in healthy volunteers and schizophrenia patients. Whilst a similar trend of a reduced behavioral performance during negative odor stimulation was observed in patients, only controls demonstrated a significantly higher response time and a reduced number of correct reactions during higher working memory demands (2-back). Patients, on the other hand, revealed an increase in false alarms during both conditions. The present data indicate a differential effect of negative mood induction on working memory performance in schizophrenia patients and healthy subjects. D

Neuropsychopharmacology, 1999

Olfactory dysfunction in patients with schizophrenia has been a topic of increasing interest, with deficits in odor identification, detection threshold sensitivity, discrimination, and memory being reported. Despite increasing knowledge, controversy has existed about possible differential deficits among olfactory tests as well as the influences of gender, smoking, and medication status on olfactory measures. To help elucidate some of this controversy, we conducted a qualitative and quantitative (meta-analytic) review of the English language literature on olfaction in schizophrenia. Moderator variables such as gender, medication status, and smoking history were also examined. Results indicated that substantial olfactory deficits, across all domains, are observed in patients with schizophrenia. No differential deficits were observed across domains of odor identification, detection threshold sensitivity, discrimination, and memory. The influences of gender, medication status, and smoking on effect sizes were not significant across studies. This supports the hypothesis of primary dysfunction in the olfactory system that is regulated by brain regions where structural and functional abnormalities have also been reported in neuroimaging studies.