Sally Szymanski

Methylphenidate increases thought disorder in recent onset schizophrenics, but not in normal controls

The effects of apomorphine and methylphenidate on thought disorder, as measured by the Thought Disorder Index, in schizophrenic patients and in normal controls were evaluated. Methylphenidate, but not apomorphine, increased thought disorder in patients. Neither drug significantly increased thought disorder in controls.

Gadolinium-DTPA enhanced gradient echo magnetic resonance scans in first episode of psychosis and chronic schizophrenic patients

Ten male schizophrenic patients underwent Gadolinium-DTPA (Gd-DTPA) enhanced magnetic resonance (MR) imaging to determine the utility of paramagnetic contrast agents in evaluating neuropathology. MR images enhanced by Gd-DTPA demonstrated no defect in the integrity of the blood-brain barrier.

The dopamine-serotonin relationship in clozapine response

The effects of clozapine on the dopamine and serotonin systems may underlie its atypical pharmacologic and clinical profile. To examine this hypothesis, we measured dopamine and serotonin plasma and cerebrospinal (CSF) metabolites and the relationship of these values to treatment response in 19 neuroleptic refractory and intolerant schizophrenic patients. Only a small change in the CSF and plasma homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5HIAA) levels was found. However, the pretreatment CSF HVA/5HIAA ratio and, to a lesser extent, the CSF HVA level predicted treatment response. These results suggest that the modest relationship between HVA and 5-HIAA and treatment response supports the involvement of both neurotransmitters in the pathophysiology of schizophrenia.

Behavioural effects of IV MCPP in schizophrenia

The effect of the serotonergic system on psychotic behaviour and sehizophrenia has been recently studied. Meta-chlorophenylpiperazine (MCPP) is a direct-acting 5HT receptor agonist which has been shown to have both neurochemical and behavioural effects in schizophrenic subjects. In this study, we report the behavioural effect of I.V. MCPP administration in a cohort of new-onset and chronic schizophrenics. clozapine trial. Patients were rated for the presence of psychopathological and tardive dyskinesia at regular intervals. Plasma and cerebrospinal fluid homovanillic acid (pHVA, CSF HVA) and cerebrospinal 5hydroxyindoleacetic acid (CSF SHIAA) levels were collected at baseline and treatment week 3. Data from 19 DSM III schizophrenic and schizoaffective disorder patients were examined. The sample was 68% male, 88% treatment refractory, 53% had tardive dyskinesia and the mean age was 29.5k6.3 years. Dividing the sample into clozapine responders vs nonresponders showed that the responders had both a lower baseline CSF HVA levels (pc.08) and a CSF HVA/SHIAA ratio (pi.04). Plasma HVA levels were not associated with CSF HVA values but with CSF SHIAA levels.