Neurotransmitters in Treatment Resistant Schizophrenia Patients With add-on Sodium Benzoate

All participants were scanned using a 1.5 Tesla GE scanner with eight channel head coils. 1H-MRS was performed to assess the concentrations of excitatory, glutamine, glutamate, glutamate complex (Glx), GABA and other neurometabolites. A three-dimensional T1-weighted inversion recovery magnetic resonance imaging (MRI) scan was performed in all participants, axial MRI three-dimensional brain volume, echo time (TE) = 2.9 ms, repetition time (TR) = 7.7, inversion time = 450 ms, flip angle = 12°, field of view =230 mm, matrix size = 256 × 256, and slice thickness = 1.0 mm

The PANSS is a clinical tool used to measure symptom severity in patients with schizophrenia. It takes approximately 45 minutes to interview a patient with schizophrenia using the PANSS. The patient is rated from 1 to 7 on 30 different symptoms based on the interview, as well as descriptions of caregivers or hospital workers. There are seven positive symptoms, seven negative symptoms, and 16 general psychopathological traits.

Specifically, for the cognitive function measurement, the WAIS-IV scale was used that comprises of five items: full-scale IQ (FSIQ), verbal comprehension index (VCI), perceptual reasoning index (PRI), WMI, and processing speed index (PSI), all of which are presented as different aspects of cognitive evaluation.

The CPT-3, is a computer assessment that evaluates attention-related deficits generally performed in ADHD. The test requires examinees to press the space bar when any letter appears, except for the letter "X." The entire test has 360 trials and takes approximately 14 minutes to administer. CPT-3 yields 10 Tscores: Omissions (OM), Variability (VAR), Commissions (COM), Perseveration (PER), Detectability (DET), Response Style (RS), Hit Reaction Time (HRT), HRT Block Change (BC), HRT Standard Deviation (HRT SD), and HRT Inter-Stimulus Interval (ISI) change, based on four different domains of attention: inattentiveness, impulsivity, sustained attention, and vigilance. The CPT-3 also includes an internal validity check which notifies the administrator that the administration is invalid if the examinee had too few hits on targets, an omission rate higher than 25%, or if there was a timing problem regarding administration.

WCST Computer Version 4-Research Edition was used in this study, and patients were required to match response cards to four stimulus cards along one of three dimensions (colour, form, or number) on the basis of verbal feedback (correct or wrong) without providing any information about the dimensions. Once the subject sorted a series of 10 cards into one category, the subject was asked to sort the cards again by a different category. In the present study, 64 cards were used. All definitions of the indices have been described in the WCST manual.