Working memory span and motor and cognitive speed in schizophrenia.

Objective: The aim of this study was to investigate the verbal working memory deficit and decrease of motor and cognitive speed in patients with schizophrenia, and to clarify their associations with negative and depressive symptomatology.

Methods: Forty patients with schizophrenia and 41 healthy control individuals were administered the backward digit span to assess the working memory capacity, along with 3 tests of processing speed.

Results: Patients demonstrated reduced backward digit span, as well as decreased motor and cognitive speed.

Visual memory errors in schizophrenic patients with auditory and visual hallucinations.

Hallucinations have been found associated with false detection or false recognition of acoustic/verbal material in several studies. We investigated whether they were also linked with false recognition of pictures. Furthermore, an association between hallucinations and deficits in remembering temporal context was observed in previous research on schizophrenia.

Temporal context discrimination in patients with schizophrenia: associations with auditory hallucinations and negative symptoms.

Background: A deficit in remembering the temporal context of events (a type of source memory) has been observed in schizophrenia, and suggested to be associated with positive symptoms.

Methods: In order to investigate memory for temporal context, we administered a list discrimination task to a sample of schizophrenia patients and a sample of healthy controls. Participants were required to learn two lists of mixed high- and low-frequency words separated by 10 min, then to remember whether each word had been presented in the first or in the second list.

Cortical effects of quetiapine in first-episode schizophrenia: a preliminary functional magnetic resonance imaging study.

Background: Quetiapine improves both psychotic symptoms and cognitive function in schizophrenia. The neural basis of these actions is poorly understood.

Methods: Three subject groups underwent a single functional magnetic resonance imaging (fMRI) session: drug-naive (n = 7) and quetiapine-treated samples of patients with schizophrenia (n = 8) and a healthy control group (n = 8).

Clinical effectiveness in first-episode patients.

Managing patients with first-episode schizophrenia is a challenging task for psychiatrists. Early diagnosis and effective intervention are vital to achieving long-term positive clinical outcomes among first-episode patients. Although these patients are the most responsive to treatment, they are also more susceptible to adverse events.

Atypical antipsychotic drugs and tardive dyskinesia: relevance of D2 receptor affinity.

Evidence suggests atypical antipsychotic treatment is associated with a lower incidence of tardive dyskinesia (TD) than typical antipsychotic drugs, and is a potential antidyskinetic treatment. We present the case of a middle-aged woman never previously exposed to antipsychotic treatment who developed TD after 6 months of olanzapine monotherapy. Substitution of quetiapine for olanzapine alleviated her TD symptoms.

Is regionally selective D2/D3 dopamine occupancy sufficient for atypical antipsychotic effect? an in vivo quantitative [123I]epidepride SPET study of amisulpride-treated patients.

Objective: Atypical antipsychotic drug treatment is clinically effective with a low risk of extrapyramidal symptoms. Explanations for the mechanism underlying this beneficial therapeutic profile of atypical over typical antipsychotic agents include 1) simultaneous antagonism of dopamine D(2) and serotonin 5-HT(2A) receptors or 2) selective action at limbic cortical dopamine D(2)-like receptors with modest striatal D(2) receptor occupancy. Amisulpride is an atypical antipsychotic drug with selective affinity for D(2)/D(3) dopamine receptors and provides a useful pharmacological model for examining these hypotheses.

Optimizing limbic selective D2/D3 receptor occupancy by risperidone: a [123I]-epidepride SPET study.

Selective action at limbic cortical dopamine D2-like receptors is a putative mechanism of atypical antipsychotic efficacy with few extrapyramidal side effects. Although risperidone is an atypical antipsychotic with high affinity for D2 receptors, low-dose risperidone treatment is effective without inducing extrapyramidal symptoms. The objective was to test the hypothesis that treatment with low-dose risperidone results in 'limbic selective' D2/D3 receptor blockade in vivo.

Typical antipsychotic drugs -- D(2) receptor occupancy and depressive symptoms in schizophrenia.

We tested the hypothesis that the degree of striatal dopamine D(2) receptor blockade induced by typical antipsychotic treatment directly correlates with the presence and severity of depressive symptoms in schizophrenia. Clinical and [(123)I]-IBZM single-photon emission tomography (SPET) scan data obtained from 18 typical antipsychotic treated schizophrenic patients was analysed to evaluate the relationship between striatal D(2) receptor occupancy and the depressive subscale of the Brief Psychiatric Rating Scale (BPRS-D). Striatal D(2) receptor occupancy by typical antipsychotic drugs was significantly positively correlated with BPRS-D scores (r=0.

New targets for antipsychotics.

Atypical antipsychotic drugs have a favorable side effect profile compared with older neuroleptics. Clozapine exhibits superior clinical efficacy in resistant schizophrenia. The neurochemical profile of these atypical agents suggests two distinct strategies in the development of novel antipsychotic drugs.