The Trajectory of Prefrontal GABA Levels in Initially Antipsychotic-Naïve Patients With Psychosis During 2 Years of Treatment and Associations With Striatal Cerebral Blood Flow and Outcome.

Background: GABAergic (gamma-aminobutyric acidergic) function in the prefrontal cortex seems dysfunctional in patients with first-episode psychosis, but the impact of longer-term treatment and relationship to clinical outcomes and striatal activity are unknown.

Methods: A longitudinal study of 39 antipsychotic-naïve and benzodiazepine-free patients with psychosis (22.4 ± 5.

Cerebral blood flow in striatum is increased by partial dopamine agonism in initially antipsychotic-naïve patients with psychosis.

Background: Resting cerebral blood flow (rCBF) in striatum and thalamus is increased in medicated patients with psychosis, but whether this is caused by treatment or illness pathology is unclear. Specifically, effects of partial dopamine agonism, sex, and clinical correlates on rCBF are sparsely investigated. We therefore assessed rCBF in antipsychotic-naïve psychosis patients before and after aripiprazole monotherapy and related findings to sex and symptom improvement.

Dopaminergic Activity in Antipsychotic-Naïve Patients Assessed With Positron Emission Tomography Before and After Partial Dopamine D Receptor Agonist Treatment: Association With Psychotic Symptoms and Treatment Response.

Background: Dopamine activity has been associated with the response to antipsychotic treatment. Our study used a four-parameter model to test the association between the striatal decarboxylation rate of F-DOPA to F-dopamine (k) and the effect of treatment on psychotic symptoms in antipsychotic-naïve patients with first-episode psychosis. We further explored the effect of treatment with a partial dopamine D receptor agonist (aripiprazole) on k and dopamine synthesis capacity (DSC) determined by the four-parameter model and by the conventional tissue reference method.