Abstract
Schizophrenia spectrum disorders (SZ) are characterized by impairments in probabilistic reinforcement learning (RL), which is associated with dopaminergic circuitry encompassing the prefrontal cortex and basal ganglia. However, there are no studies examining dopaminergic genes with respect to probabilistic RL in SZ. Thus, the aim of our study was to examine the impact of dopaminergic genes on performance assessed by the Probabilistic Selection Task (PST) in patients with SZ in comparison to healthy control (HC) subjects. In our study, we included 138 SZ patients and 188 HC participants. Genetic analysis was performed with respect to the following genetic polymorphisms: rs4680 in COMT, rs907094 in DARP-32, rs2734839, rs936461, rs1800497, and rs6277 in DRD2, rs747302 and rs1800955 in DRD4 and rs28363170 and rs2975226 in DAT1 genes. The probabilistic RL task was completed by 59 SZ patients and 95 HC subjects. SZ patients performed significantly worse in acquiring reinforcement contingencies during the task in comparison to HCs. We found no significant association between genetic polymorphisms and RL among SZ patients; however, among HC participants with respect to the DAT1 rs28363170 polymorphism, individuals with 10-allele repeat genotypes performed better in comparison to 9-allele repeat carriers. The present study indicates the relevance of the DAT1 rs28363170 polymorphism in RL in HC participants.
Highlights
Schizophrenia (SZ) is a complex disorder with diverse symptomatology, including positive symptoms, negative symptoms, and cognitive dysfunction [1,2,3]
The distribution of specific genotypes followed the Hardy–Weinberg equilibrium (HWE) (p-value > 0.05), except for two polymorphisms: DRD4 rs747302 in SZ patients and DAT1 rs2975226 among healthy control (HC) participants, which were excluded from further analysis
Among SZ patients, we found no significant associations between performance during the training phase on Probabilistic Selection Task (PST) and clinical measures (SAPS, Scales for the Assessment of Negative Symptoms (SANS), Brief Psychiatric Rating Scale (BPRS), Montgomery–Asberg Depression Rating Scale (MADRS), BDI), general functioning (GAF), chlorpromazine equivalent dose (CPZ), or age of onset or illness duration (p > 0.05) (Table A2)
Summary
Schizophrenia (SZ) is a complex disorder with diverse symptomatology, including positive symptoms, negative symptoms, and cognitive dysfunction [1,2,3]. Dopamine (DA) has been linked to both positive and negative SZ symptoms [5], with irregular DA release hypothesized to ascribe aberrant salience to irrelevant stimuli [6]. Negative PE are encoded by phasic dips or pauses in dopaminergic activity when rewards are expected but not received [9]. These phasic bursts and dips in DA modify synaptic plasticity in the connections between prefrontal cortical areas (PFC)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
