Early-Onset Schizophrenia Showed Similar but More Severe Olfactory Identification Impairment Than Adult-Onset Schizophrenia

Association of serum interleukin-6 with negative symptoms in stable early-onset schizophrenia

BACKGROUND

Accumulating evidence suggests that the inflammatory cytokine interleukin-6 (IL-6) contributes to the pathophysiology of psychiatric disorders. However, there was no study concerning the relationship between IL-6 concentrations and clinical features in the chronic phase of early-onset schizophrenia (EOS).

AIM

To investigate the relationship between serum IL-6 concentration and the clinical features of EOS.

METHODS

We measured serum IL-6 Levels from 74 patients with chronic schizophrenia, including 33 with age at onset < 21 years (EOS group) and 41 with onset ≥ 21 years in [adult-onset schizophrenia (AOS) group], and from 41 healthy controls. Symptom severities were evaluated using the Positive and Negative Syndrome Scale (PANSS).

RESULTS

Serum IL-6 concentrations were higher in both EOS and AOS groups than healthy controls (F = 22.32, P < 0.01), but did not differ significantly between EOS and AOS groups (P > 0.05) after controlling for age, body mass index, and other covariates. Negative symptom scores were higher in the EOS group than the AOS group (F = 6.199, P = 0.015). Serum IL-6 concentrations in the EOS group were negatively correlated with both total PANSS-negative symptom score (r = -0.389, P = 0.032) and avolition/asociality subscore (r = -0.387, P = 0.026).

CONCLUSION

Patients with EOS may have more severe negative symptoms than those with adult-onset schizophrenia during the chronic phase of the illness. IL-6 signaling may regulate negative symptoms and its avolition/asociality subsymptoms among the early-onset chronic schizophrenic patients.

Neural mechanism underlying the beneficial effect of Theory of Mind psychotherapy on early-onset schizophrenia: a randomized controlled trial

BACKGROUND

Psychosocial interventions have emerged as an important component of a comprehensive therapeutic approach in early-onset schizophrenia, typically representing a more severe form of the disorder. Despite the feasibility and efficacy of Theory of Mind (ToM) psychotherapy for schizophrenia, relatively little is known regarding the neural mechanism underlying its effect on early-onset schizophrenia.

METHODS

We performed a randomized, active controlled trial in patients with early-onset schizophrenia, who were randomly allocated into either an intervention (ToM psychotherapy) or an active control (health education) group. Diffusion tensor imaging data were collected to construct brain structural networks, with both global and regional topological properties measured using graph theory.

RESULTS

We enrolled 28 patients with early-onset schizophrenia in our study. After 5 weeks of treatment, both the intervention and active control groups showed significant improvement in psychotic symptoms, yet the improvement was greater in the intervention group. Importantly, in contrast with no brain structural network change after treatment in the active control group, the intervention group showed increased nodal centrality of the left insula that was associated with psychotic symptom improvement.

LIMITATIONS

We did not collect important information concerning the participants' cognitive abilities, particularly ToM performance.

CONCLUSION

These findings suggest a potential neural mechanism by which ToM psychotherapy exerts a beneficial effect on early-onset schizophrenia via strengthening the coordination capacity of the insula in brain structural networks, which may provide a clinically translatable biomarker for monitoring or predicting responses to ToM psychotherapy.Clinical trial registration: NCT05577338; ClinicalTrials.gov.

Olfactory Dysfunction in Mental Illness

PURPOSE OF REVIEW

Olfactory dysfunction contributes to the psychopathology of mental illness. In this review, we describe the neurobiology of olfaction, and the most common olfactory alterations in several mental illnesses. We also highlight the role, hitherto underestimated, that the olfactory pathways play in the regulation of higher brain functions and its involvement in the pathophysiology of psychiatric disorders, as well as the effect of inflammation on neurogenesis as a possible mechanism involved in olfactory dysfunction in psychiatric conditions.

RECENT FINDINGS

The olfactory deficits present in anxiety, depression, schizophrenia or bipolar disorder consist of specific alterations of different components of the sense of smell, mainly the identification of odours, as well as the qualifications of their hedonic valence (pleasant or unpleasant). Epidemiological findings have shown that both environmental factors, such as air pollutants, and inflammatory disease of the upper respiratory tract, can contribute to an increased risk of mental illness, at least in part, due to peripheral inflammatory mechanisms of the olfactory system. In this review, we describe the neurobiology of olfaction, and the most common olfactory function alterations in several psychiatric conditions and its role as a useful symptom for the differential diagnosis. We also highlight the effect of inflammation on neurogenesis as a possible mechanism involved in olfactory dysfunction in these psychiatric conditions.

Variations in olfactory function among bipolar disorder patients with different episodes and subtypes

Purpose

Most studies on olfactory function in individuals with bipolar disorder (BD) have not distinguished between the different subtypes or between the acute phase (mania or depression) and euthymic state. In this study, we compared olfactory function among BD patients with different subtypes and episodes to explore the potential use of olfactory function as a biomarker for the early identification of BD.

Patients and methods

The study sample consisted of 117 BD patients who were hospitalized between April 2019 and June 2019, and 47 healthy volunteers as controls. The BD patients were divided into a bipolar I disorder (BD I) (n = 86) and bipolar II disorder (BD II) group (n = 31) according to the different subtypes, and divided into depressive BD (n = 36), manic BD (n = 44), or euthymic BD (n = 37) groups according to the types of episodes they experienced. We assessed olfactory sensitivity (OS) and olfactory identification (OI) via the Sniffin' Sticks test and used the Hamilton Depression Rating Scale (HAMD) and Young Manic Rating Scale (YMRS) to evaluate BD characteristics among all subjects.

Results

Compared with controls, the participants with BD showed decreased OS and OI. We found statistically significant differences in OS and OI between the BD I group and controls, as well as differences in OS between the BD I and BD II group. Least-significant difference multiple comparisons revealed statistically significant differences in OS between the depressive BD group, manic BD group and controls and also between the manic BD and euthymic BD group. OI was positively correlated with the YMRS score in the BD I group and OS was negatively correlated with the HAMD score in the BD II group.

Conclusion

This may be the first study to compare olfactory function in patients with BD I vs. BD II via pairwise comparisons. Our findings suggest that OS may have potential as a biomarker for distinguishing the different subtypes of BD and as a state-related biomarker for differentiating the acute phase from the euthymic state of BD. However, further prospective research is warranted.

Olfactory impairment in psychiatric disorders: Does nasal inflammation impact disease psychophysiology?

Olfactory impairments contribute to the psychopathology of mental illnesses such as schizophrenia and depression. Recent neuroscience research has shed light on the previously underappreciated olfactory neural circuits involved in regulation of higher brain functions. Although environmental factors such as air pollutants and respiratory viral infections are known to contribute to the risk for psychiatric disorders, the role of nasal inflammation in neurobehavioral outcomes and disease pathophysiology remains poorly understood. Here, we will first provide an overview of published findings on the impact of nasal inflammation in the olfactory system. We will then summarize clinical studies on olfactory impairments in schizophrenia and depression, followed by preclinical evidence on the neurobehavioral outcomes produced by olfactory dysfunction. Lastly, we will discuss the potential impact of nasal inflammation on brain development and function, as well as how we can address the role of nasal inflammation in the pathophysiological mechanisms underlying psychiatric disorders. Considering the current outbreak of Coronavirus Disease 2019 (COVID-19), which often causes nasal inflammation and serious adverse effects for olfactory function that might result in long-lasting neuropsychiatric sequelae, this line of research is particularly critical to understanding of the potential significance of nasal inflammation in the pathophysiology of psychiatric disorders.

Interactive Effects of Agitation and Cognitive Impairment on Odor Identification in Patients With Late-Life Depression

BACKGROUND

Late-life depression (LLD) is a risk factor for cognitive decline in older adults, and odor identification (OI) deficits are an early indicator of cognitive decline with LLD. However, neuropsychiatric symptoms (NPSs) are common in LLD and are associated with OI deficits. In subjects with LLD, when OI deficits forecast cognitive decline, whether and how NPS affects the relationship between OI and cognition still must be further explored.

OBJECTIVE

To comprehensively explore the potential effects of various NPSs on the relationship between OI and cognition in participants with LLD.

METHODS

There were 167 patients with LLD and 105 normal elderly (NE) participants. The odor identification test (Sniffin' Sticks), cognitive function assessments (global cognition, memory, executive function, attention, language, visual space), and an NPS assessment (the neuropsychiatric inventory questionnaire) were performed on the subjects. In patients with LLD, the relationship among OI, cognition and NPSs was examined using correlation analysis and moderation analysis.

RESULTS

In patients with LLD, OI was positively correlated with cognition (global cognition, memory, executive function, attention, language) and negatively associated with NPSs (agitation and aberrant motor behavior). In NE group, OI was correlated with executive function. Moderation analysis showed that there was an interactive effect of agitation and cognitive impairment (language deficit or attention deficit) on OI in patients with LLD.

CONCLUSION

The coexistence of agitation and language or attention deficit was associated with worse OI in subjects with LLD. Agitation should be considered since OI predicts cognitive decline in patients with LLD.

Odour identification impairment is a trait but not a disease-specific marker for bipolar disorders: Comparisons of bipolar disorder with different episodes, major depressive disorder and schizophrenia

OBJECTIVE

Olfactory deficits have been reported in bipolar disorder, but this finding is controversial. This study investigated whether olfactory deficit can serve as a specific marker for bipolar disorder by comparing olfactory function in different mood episodes of bipolar disorder. We also compared olfactory function in bipolar disorder and other mental disorders - namely, major depressive disorder and schizophrenia.

METHODS

The study consisted of two experiments. Experiment 1 enrolled 175 bipolar disorder patients (70 depressed subgroup, 70 manic subgroup and 35 euthymic subgroup) and 47 controls. Experiment 2 enrolled the participants from Experiment 1, along with 85 major depressive disorder and 90 schizophrenia patients. The Sniffin' Sticks test was used to evaluate odour identification ability and odour threshold (as a measure of odour sensitivity). The Hamilton Depression Rating Scale and Young Mania Rating Scale were used to assess depressive symptoms in all subjects and manic symptoms in bipolar disorder patients, respectively. We also used the Positive and Negative Syndrome Scale to assess clinical symptoms in schizophrenia patients.

RESULTS

All three bipolar disorder patient subgroups (depressed, manic and euthymic subgroup) showed reduced odour identification ability compared to controls; however, only patients in the acute phase of a mood episode (depressed, and manic subgroup) showed impaired odour sensitivity. Clinical symptoms were negatively correlated with odour sensitivity but not odour identification ability. Bipolar disorder and major depressive disorder patients showed less odour identification and sensitivity impairment than schizophrenia patients.

CONCLUSION

Odour sensitivity is a potential dopaminergic marker for distinguishing between bipolar disorder patients in acute phase vs remission, while odour identification is a trait but a nonspecific marker of bipolar disorder.

SARS-CoV-2-associated cytokine storm during pregnancy as a possible risk factor for neuropsychiatric disorder development in post-pandemic infants

A strong association between perinatal viral infections and neurodevelopmental disorders has been established. Both the direct contact of the virus with the developing brain and the strong maternal immune response originated by viral infections can impair proper neurodevelopment. Coronavirus disease 2019 (COVID-19), caused by the highly-infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently responsible for a large global outbreak and is a major public health issue. While initial studies focused on the viral impact on the respiratory system, increasing evidence suggest that SARS-CoV-2 infects other organs and tissues including the mature brain. While studies continue to determine the neuropathology associated to COVID-19, the consequences of SARS-CoV-2 infection to the developing brain remain largely unexplored. The present review discusses evidence suggesting that SARS-CoV-2 infection may have persistent effects on the course of pregnancy and on brain development. Studies have shown that several proinflammatory mediators which are increased in the SARS-CoV-2-associated cytokine storm, are also modified in other viral infections known to increase the risk of neurodevelopmental disorders. In this sense, further studies should assess the genuine effects of SARS-CoV-2 infection during pregnancy and delivery along with an extended follow-up of the offspring, including neurocognitive, neuroimaging, and electrophysiological examination. It also remains to be determined whether and by which mechanisms SARS-CoV-2 intrauterine and early life infection could lead to an increased risk of developing neuropsychiatric disorders, such as autism (ASD) and schizophrenia (SZ), in the offspring.