An Update Review to Cast Light on the Possible Role of Altered Oropharyngeal Microbiota in Differentiating True Psychosis from Malingered Psychosis in a Forensic Psychiatric Setting
Table 2
A summary of the observed oropharyngeal microbiota differences between healthy controls and patients with psychosis.
Case-control study 35 schizophrenic patients 35 healthy controls
Estimation of the prevalence and quantity of Porphyromonas gingivalis in the saliva of schizophrenic patients compared to healthy controls
A substantially higher Porphyromonas gingivalis prevalence was observed in schizophrenic patients’ saliva compared to healthy subjects. As presented by PANSS scores, the levels of Porphyromonas gingivalis levels were largely associated with the severity of the schizophrenia psychopathology, where the most robust correlation was denoted by negative symptoms.
Pilot observational exploratory study 250 schizophrenic patients (;)
Exploring the feasible bidirectional connection between periodontal disease and schizophrenia
The study indicated that patients with long histories of schizophrenia have exhibited periodontal conditions of poor quality, being demonstrated by plaque and gingival indexes. The obtained results implied the periodontal disease’s feasible role in schizophrenia pathogenesis.
Case-control study 33 healthy controls 41 schizophrenic patients
Characterization of bacteriophage genomes in the oropharynx of healthy subjects and schizophrenic patients
Lactobacillus phage phiadh was significantly higher in schizophrenic patients compared to the controls. Among schizophrenic patients, the level of Lactobacillus phage phiadh level had a correlation with an escalated rate of comorbid immunological disorders.
Case-control study 16 healthy controls 16 schizophrenic patients
Characterization of schizophrenia microbiome through the interrogation of the oropharyngeal microbiome structure concerning its functional and taxonomic diversity
Lactobacillus gasseri was detected to have a higher prevalence in psychotic patients by a factor of 400 compared to controls; however, there were noticeably lower levels of Neisseria, Haemophilus, and Capnocytophaga.
Case-control study 121 schizophrenic patients 62 patients with mania 48 patients with major depressive disorder 85 healthy controls
Confirming the link between altered oropharyngeal microbiome and schizophrenia
The study revealed that the oropharyngeal microflora of schizophrenic and manic subjects was different from that of controls. Neisseria subflava, Prevotella, and Weeksellaceae were lessened in schizophrenic or manic patients compared with the controls; nonetheless, Streptococci were elevated in the former groups. Only manic patients showed that the unique pattern has appeared in Schlegelella. There was also a positive relationship between Neisseria subflava and cognitive functioning. There was an altered beta diversity in schizophrenic and manic patients, in comparison to healthy controls.
Case-control study 80 healthy controls 43 patients with clinical high risk 85 patients with first-episode schizophrenia
Exploring the salivary microbiome among schizophrenia patients Categorizing the microbial profiles at various schizophrenia’s clinical stages Reaching an insight into the salivary microbes’ role in the schizophrenia initiation
A high rate Firmicutes/Proteobacteria ratio was observed in the salivary microbiome among schizophrenic patients. A distribution of metabolic functions of the salivary microbiome was detected in schizophrenia.
Case-control study 83 first-episode schizophrenic patients 42 clinically high-risk individuals for psychosis before its onset 78 healthy controls
Examining the link between salivary metabolomics and the schizophrenia onset
It is possible to assume differential metabolites as potential diagnostic biomarkers and show the severity of various clinical stages of the disease. The results also revealed the earlier occurrence of oral metabolism disorder than the schizophrenia onset, which is intensified and concentrated with the disease initiation. The dysbiotic salivary microbiota may cause oral metabolism, leading to schizophrenia initiation through the redox system and the peripheral inflammatory response, highlighting the significance of the oral-brain connection in schizophrenia pathogenesis.
Case-control study 9 patients with any psychotic bipolar disorder and schizophrenia-related psychosis 6 patients with nonpsychotic affective disorder 8 healthy controls
Investigating the association of oral and gut microbiome with clinical and molecular markers of schizophrenia
In this study, psychiatric cases had enrichment of pathogenic taxa and significantly higher heterogeneity of gut alpha diversity, similar to Prevotella and Veillonella, in the oral microbiome—a true categorizer of phenotype.
