Genetic aspects in schizophrenia. Receptoral theories. Metabolic theories

High number of mitochondrial DNA alterations in postmortem brain tissue of patients with schizophrenia compared to healthy controls

Previous studies have shown mitochondrial dysfunction in schizophrenia (SZ) patients, which may be caused by mitochondrial DNA (mtDNA) alterations. However, there are few studies in SZ that have analyzed mtDNA in brain samples by next-generation sequencing (NGS). To address this gap, we used mtDNA-targeted NGS and qPCR to characterize mtDNA alterations in brain samples from patients with SZ (n = 40) and healthy controls (HC) (n = 40). 35 % of SZ patients showed mtDNA alterations, a significantly higher prevalence compared to 10 % of HC. Specifically, SZ patients had a significantly higher frequency of deletions (35 vs. 5 in HC), with a mean number of deletions of 3.8 in SZ vs. 1.0 in HC. Likely pathogenic missense variants were also significantly more frequent in patients with SZ than in HC (10 vs. three HC), encompassing 14 variants in patients and three in HC. The pathogenic tRNA variant m.3243A>G was identified in one SZ patient with a high heteroplasmy level of 32.2 %. While no significant differences in mtDNA copy number (mtDNA-CN) were observed between SZ and HC, antipsychotic users had significantly higher mtDNA-CN than non-users. These findings suggest a potential role for mtDNA alterations in the pathophysiology of SZ that require further validation and functional studies.

Identification of genetic loci that overlap between schizophrenia and metabolic syndrome

Patients with schizophrenia (SCZ) frequently exhibit an elevated risk of metabolic syndrome (MetS), which may lead to a worse clinical outcome. Even though these two phenotypes are genetically linked, little is known about their shared genetic determinants. Here, we investigated whether SCZ and MetS share genetic risk factors. To examine the genetic overlap between the two disorders, we applied a comprehensive genetic overlap analysis by integrating GWAS data for SCZ (n = 320,404) and MetS (n = 291,107) at the genome, genetic variants, and gene levels. At the genome level, we observed polygenic overlap between SCZ and MetS by utilizing LDSC (r_g=-0.09, P = 1 × 10^-4) and GNOVA (rho=-0.04, P = 1.39 × 10^-8) analysis. At the SNP level, we performed conjunctional FDR (conjFDR) analysis to identify genetic variants simultaneously associated with two phenotypes. Based on conjFDR < 0.05, we identified 22 loci shared between SCZ and MetS. At the gene level, we further demonstrated that SCZ- and MetS-inferred gene expression overlapped across 49 GTEx tissues and highlighted the PCCB and KCTD13 genes as putative mediators of the genetic association. Overall, these findings shed novel light on the association between SCZ and MetS, and potentially enhance our knowledge of the high comorbidity and genetic processes that overlap between the two disorders.

Antipsychotic polypharmacy in adult patients diagnosed with schizophrenia: A retrospective study

Antipsychotic polypharmacy (APP) is a common practice in the treatment of schizophrenia. In this study, we aimed to identify the prevalence of APP in our department, as well as the trends associated with co-prescribing antipsychotics. We collected data from the medical records of all 193 inpatients diagnosed with schizophrenia who were admitted to Prof. Dr. Alexandru Obregia Clinical Psychiatry Hospital (Bucharest, Romania), Department 9, during January 2019-December 2019. Demographic characteristics of the patients, clinical diagnosis, psychiatric admission type and duration of hospitalization were examined. Data regarding the antipsychotic regimen at discharge and other psychotropic drugs used were collected. A total of 69 (35.75%) patients received more than 2 antipsychotics upon discharge. Patients treated with APP did not differ in regards to sex, age, education level, employment status, marital status, living situation, type of admission from those receiving antipsychotic monotherapy (APM). Prolonged hospitalization was found to be an independent predictor of APP (P=0.014). Most of the combinations used in our unit included clozapine (47.8%), and the most frequently used treatment in the APP group was the combination of paliperidone and clozapine (14.5%). In the APP group, 30 (43.5%) patients included in their regimen was a long-acting intramuscular antipsychotic. There was no significant difference in terms of the use of mood stabilizers, antiparkinsonian drugs or anxiolytics between the APP and the APM group; yet, a higher prevalence of antidepressant use, although not statistically significant (P=0.067), in the APP group compared to the APM group, was observed. The use of APP as a long-term regimen is a common practice in our department, as it is worldwide. There is a great need for randomized-control trials and evidence-based studies in order to define the safest and most effective combinations of antipsychotics and also the characteristics of patients that may benefit from these combinations.

Understanding the genetics and neurobiological pathways behind addiction (Review)

The hypothesis issued by modern medicine states that many diseases known to humans are genetically determined, influenced or not by environmental factors, which is applicable to most psychiatric disorders as well. This article focuses on two pending questions regarding addiction: Why do some individuals become addicted while others do not? along with Is it a learned behavior or is it genetically predefined? Recent data suggest that addiction is more than repeated exposure, it is the synchronicity between intrinsic factors (genotype, sex, age, preexisting addictive disorder, or other mental illness), extrinsic factors (childhood, level of education, socioeconomic status, social support, entourage, drug availability) and the nature of the addictive agent (pharmacokinetics, path of administration, psychoactive properties). The dopamine-mesolimbic motivation-reward-reinforcement cycle remains the most coherent physiological theory in addiction. While the common property of addictive substances is that they are dopamine-agonists, each class has individual mechanisms, pharmacokinetics and psychoactive potentials.

Morphopathological approaches in alcoholism

Alcohol morphopathology has been studied over time, being a central interest of specialists, due to the negative consequences it has on the brain and the entire central nervous system (CNS). This paper is a review of the literature that emphasizes one of the problems of the modern world, that of the compulsive consume of alcohol, having a great global spread. The studies analyzed are topical, being carried out in recent years and consider the harmful effects of alcohol on brain formations, such as corpus callosum, gray and white matter, hippocampus, and hypothalamus. At the same time, alcohol is a risk factor for cardiovascular diseases, and in combination with other harmful substances, increases the risk of various diseases, such as neurodegeneration. Abusive alcohol consumption can bring epigenetic changes and alter the typical functioning of cognitive functions. This paper focuses on alcohol consumption on adolescents and young people, which is a serious problem nowadays. Alcohol also influences the way of behavioral expression, becoming a risk for the development of mental disorders. However, alcohol withdrawal is another problem with different effects and must be in the attention of specialists.