Qing Rui

Effects of catecholamine depletion on D2 receptor binding, mood, and attentiveness in humans: a replication study

The effect of catecholamine depletion, achieved by per-oral administration of 5250 mg alpha-methyl-para-tyrosine (AMPT) given in the 29 h prior to [11C]raclopride positron emission tomography (PET) was studied on measures of dopamine (DA) release, mood, and attention. Neostriatal DA levels in vivo were estimated by comparing the neostriatal DA D(2) receptor binding potential (D(2)RBP) before and after catecholamine depletion using PET and the radiotracer [11C]raclopride. Six healthy subjects completed the protocol. The AMPT treatment increased D(2)RBP significantly by 13.3+/-5.9% (average+/-standard deviation) and decreased plasma levels of the DA metabolite homovanillic acid (HVA) by 62+/-17%, and levels of the norepinephrine (NE) metabolite 3-methoxy-4-hydroxyphenethyleneglycol (MHPG) by 66+/-5%. Catecholamine depletion resulted in decreased happiness, euphoria, energy, talkativeness, vigor, and attentiveness, and in increased sleepiness, fatigue, sedation, and eye blink rate (EBR). These changes were not correlated with the D(2)RBP increments. The results of this study are overall consistent with previous findings by our group using the same methodology in a different cohort of six healthy subjects.

Reduced anterior internal capsule and thalamic volumes in first-episode psychosis.

BACKGROUND The thalamus is the gateway for sensory and motor information en route to the cortex. Information is processed via thalamocortical and corticothalamic pathways coursing through the internal capsules. In this study, we investigated the relationship between the anterior limb of the internal capsule, posterior limb of the internal capsule, and thalamus in first-episode psychosis (FEP). METHODS Twenty-nine FEP subjects (26 DSM-IV schizophrenia, 2 schizoaffective disorder, 1 psychosis not otherwise specified) and 22 healthy volunteers participated in this study. Anterior limb of the internal capsule (AIC), posterior limb of the internal capsule (PIC), and the thalamus volumes were manually determined from MRI scans. RESULTS FEP subjects had reduced AIC volumes (F(1,45)=6.18, p=0.017) and thalamic volumes (F(1,45)=8.00, p=0.007) compared to healthy volunteers. PIC volumes did not differ. Significant correlations between AIC volumes and thalamic volumes were observed in subjects with FEP, but not in healthy volunteers. Negative relationships between thalamic volumes and symptom severity were also observed. CONCLUSIONS The AIC and thalamic volumes were reduced in subjects with FEP compared to healthy volunteers. Abnormalities in thalamocortical and orticothalamic pathways may contribute to functional disruption of neural circuits in psychosis.

Treatment of a first episode of psychotic illness with quetiapine : An analysis of 2 year outcomes

BACKGROUND The first episode of a psychotic disorder provides a unique opportunity to initiate optimal treatment but when a new medication becomes available, little data exist to guide the appropriate use in this population. OBJECTIVES The objectives were to determine the optimal doses and titration of quetiapine for this group and to measure outcomes (including symptom response, social functioning, mood alterations, motor symptoms, metabolic parameters and cognitive functioning) over 2 years of treatment with quetiapine. DESIGN Thirty nine subjects with a first episode of psychosis referred to the Nova Scotia Early Psychosis Program in Halifax, Canada, were invited to participate in this study. Standardized clinical, laboratory, and neuropsychological assessments were performed at baseline and following treatment with quetiapine at intervals out to 2 years. RESULTS Quetiapine was effective in treating the psychotic and mood symptoms while not causing extra-pyramidal signs or symptoms (EPSS). Pre-existing motor dysfunction improved. No anticholinergic medications were required. Several domains of cognitive function also improved (sustained attention, the number of perseverative errors, visuomotor speed and sequencing, verbal fluency and verbal memory). Weight gain was observed along with increases in cholesterol levels but there was no glucose dysregulation. CONCLUSIONS The results of this two year, naturalistic study of people with a first episode of psychosis indicated that quetiapine was well tolerated and effective for this population. Significant improvements in cognitive functioning also provided evidence for potential longer-term benefits of early and optimal treatment with this agent. However, monitoring metabolic parameters, as recommended for other atypicals, is likely prudent.