Cluster analysis dissecting cognitive deficits in older adults with major depressive disorder and the association with neurofilament light chain

BACKGROUND

Cognitive impairment is a growing problem with increasing burden in global aging. Older adults with major depressive disorder (MDD) have higher risk of dementia. Neurofilament light chain (NfL) has been proven as a potential biomarker in neurodegenerative disease, including dementia. We aimed to investigate the association between cognitive deficits and NfL levels in older adults with MDD.

METHODS

In this cross-sectional study, we enrolled 39 MDD patients and 15 individuals with mild neurocognitive disorder or major neurocognitive disorder, Alzheimer's type, as controls, from a tertiary psychiatric hospital. Both groups were over age 65 and with matched Mini-Mental State Examination (MMSE) score. Demographic data, clinical variables, and plasma NfL levels were obtained. We used cluster analysis according to their cognitive profile and estimated the correlation between plasma NfL levels and each cognitive domain.

RESULTS

In the MDD group, participants had higher rate of family psychiatry history and current alcohol use habit compared with controls. Control group of neurocognitive disorders showed significantly lower score in total MMSE and higher plasma NfL levels. Part of the MDD patients presented cognitive deficits clustered with that of neurocognitive disorders (cluster A). In cluster A, the total MMSE score (r=-0.58277, p=0.0287) and the comprehension domain (r=-0.71717, p=0.0039) were negatively correlated to NfL levels after adjusting for age, while the associations had not been observed in the other cluster.

CONCLUSIONS

We noted the negative correlation between NfL levels and cognition in MDD patients clustered with neurodegenerative disorder, Alzheimer's type. NfL could be a promising candidate as a biomarker to predict subtype of patients in MDD to develop cognitive decline. Further longitudinal studies and within MDD cluster analysis are required to validate our findings for clinical implications.

Crosstalk between Schizophrenia and Metabolic Syndrome: The Role of Oxytocinergic Dysfunction

The high prevalence of metabolic syndrome in persons with schizophrenia has spurred investigational efforts to study the mechanism beneath its pathophysiology. Early psychosis dysfunction is present across multiple organ systems. On this account, schizophrenia may be a multisystem disorder in which one organ system is predominantly affected and where other organ systems are also concurrently involved. Growing evidence of the overlapping neurobiological profiles of metabolic risk factors and psychiatric symptoms, such as an association with cognitive dysfunction, altered autonomic nervous system regulation, desynchrony in the resting-state default mode network, and shared genetic liability, suggest that metabolic syndrome and schizophrenia are connected via common pathways that are central to schizophrenia pathogenesis, which may be underpinned by oxytocin system dysfunction. Oxytocin, a hormone that involves in the mechanisms of food intake and metabolic homeostasis, may partly explain this piece of the puzzle in the mechanism underlying this association. Given its prosocial and anorexigenic properties, oxytocin has been administered intranasally to investigate its therapeutic potential in schizophrenia and obesity. Although the pathophysiology and mechanisms of oxytocinergic dysfunction in metabolic syndrome and schizophrenia are both complex and it is still too early to draw a conclusion upon, oxytocinergic dysfunction may yield a new mechanistic insight into schizophrenia pathogenesis and treatment.

Associations of Genetic Variants of Methylenetetrahydrofolate Reductase and Serum Folate Levels with Metabolic Parameters in Patients with Schizophrenia

The one-carbon metabolism pathway is a suitable candidate for studying the genetic and epigenetic factors contributing to metabolic abnormalities in patients with schizophrenia. We recruited 232 patients with schizophrenia and analyzed their serum folate, vitamin B12, and homocysteine levels and metabolic parameters to investigate the associations of genetic variants of methylenetetrahydrofolate reductase (MTHFR) and folate levels with metabolic parameters. MTHFR C677T and MTHFR A1298C were genotyped. Results showed that MTHFR 677T allele carriers had lower levels of total cholesterol and low-density lipoprotein cholesterol than those with the 677CC genotype. Metabolic parameters did not differ between MTHFR 1298C and 1298AA carriers. Patients with a low folate level had a lower high-density lipoprotein cholesterol level than those with a normal folate level, but the effect disappeared after adjustment for age, sex, and types of antipsychotics used. We found significant interactions between MTHFR A1298C and the folate level status (low vs. normal) in terms of body mass index and waist circumference. In conclusion, genetic variants in one-carbon metabolism might play a role in antipsychotic-induced metabolic abnormalities. Prospective studies on drug-naïve, first-episode patients with schizophrenia are warranted to identify key regions of DNA methylation changes accounting for antipsychotic-induced metabolic abnormalities.

The Relationships Between Hyperprolactinemia, Metabolic Disturbance, and Sexual Dysfunction in Patients With Schizophrenia Under Olanzapine Treatment

The aim of the study was to assess the relationship between prolactin levels and sexual dysfunction in patients with schizophrenia who use olanzapine medication. The potential risk factors of hyperprolactinemia and sexual dysfunction were also investigated. Patients with schizophrenia undergoing olanzapine monotherapy were invited to participate in this cross-sectional study. The Arizona Sexual Experiences Scale (ASEX) and the Positive and Negative Syndrome Scale were used to evaluate subjective sexual dysfunction and psychopathology, respectively. Levels of prolactin and metabolic parameters were also measured. In total, 279 participants with schizophrenia were recruited. The overall incidences of hyperprolactinemia, sexual dysfunction, and metabolic syndrome were 51.6, 53.8, and 43.7%, respectively. Higher ASEX scores, higher insulin levels, female sex, and younger age were associated with hyperprolactinemia. Prolactin level was significantly correlated with ASEX score. Elevated prolactin levels, concomitant antidepressant, increased insulin resistance, longer illness duration, and female sex were associated with sexual dysfunction. Female participants recorded higher levels of sexual dysfunction than their male counterparts did, whereas male participants had comparatively lower prolactin levels and lower rates of spousal partnership. Hyperprolactinemia, metabolic syndrome, and sexual dysfunction are prevalent in patients with schizophrenia treated with olanzapine. Clinicians should maintain awareness of these problems and monitor them regularly with their patients.

Effects of omega-3 polyunsaturated fatty acids supplements on psychopathology and metabolic parameters in schizophrenia: A meta-analysis of randomized controlled trials

BACKGROUND

Several monotherapy and augmentation strategies have been introduced to improve the treatment of schizophrenia. The benefits of omega-3 polyunsaturated fatty acids in patients with mental disorders is becoming increasingly acknowledged. However, its role in the treatment of schizophrenia raises complex considerations about which there has been little consensus. The aim of this study was to synthesize the findings of randomized controlled trials that were conducted to determine the efficacy and safety of omega-3 polyunsaturated fatty acids in patients with schizophrenia.

METHODS

The MEDLINE, Embase, Cochrane, Scopus, and Web of Science databases were searched for relevant literature. The primary outcome was changes in psychopathology and the secondary outcomes were changes in metabolic parameters and safety profiles.

RESULTS

Twenty double-blind randomized controlled trials in 1494 patients were included. Omega-3 polyunsaturated fatty acids augmentation was associated with significantly improved psychopathology in patients with schizophrenia, particularly general psychopathology and positive symptoms but not negative symptoms. Patients who were severely ill and received omega-3 polyunsaturated fatty acids containing eicosapentaenoic acid >1 g/d showed significant improvement. A favorable effect of omega-3 polyunsaturated fatty acids supplements on serum triglycerides was also demonstrated. Omega-3 polyunsaturated fatty acids are well-tolerated and safe in patients with schizophrenia.

CONCLUSIONS

These findings tentatively support the use of omega-3 polyunsaturated fatty acids as a potential augmentation strategy in schizophrenia. Further research in larger samples is warranted to clarify the optimal dosage and the correct proportions of omega-3 polyunsaturated fatty acids to administer, together with elucidation of the underlying mechanisms.

The Role of Adiponectin in the Pathogenesis of Metabolic Disturbances in Patients With Schizophrenia

Antipsychotic-induced metabolic disturbance is a common adverse event occurring in patients treated with antipsychotic drugs. The mechanisms underlying metabolic dysregulation are complex, involving various neurochemical and hormonal systems, the interaction of genetic and lifestyle risk factors, and the antipsychotic drug prescribed. Recently, there has been increasing interest in the relationship between antipsychotic-induced metabolic disturbances and body weight regulatory hormones such as adiponectin. Adiponectin, an adipocyte-derived protein related to insulin sensitivity, weight gain, and anti-inflammation, has attracted great attention because of its potential role of being a biomarker to predict cardiovascular and metabolic diseases. Previous studies regarding the effects of antipsychotics on blood adiponectin levels have shown controversial results. Several factors might contribute to those inconsistent results, including different antipsychotic drugs, duration of antipsychotic exposure, age, sex, and ethnicity. Here we summarize the existing evidence on the link between blood adiponectin levels and metabolic disturbances related to antipsychotic drugs in patients with schizophrenia. We further discuss the effects of individual antipsychotics, patients' gender, ethnicity, age, and treatment duration on those relationships. We propose that olanzapine and clozapine might have a time-dependent biphasic effect on blood adiponectin levels in patients with schizophrenia.

A randomized, placebo-controlled trial of sustained-release dextroamphetamine for treatment of methamphetamine addiction

Sixty treatment-seeking individuals with methamphetamine (MA) dependence entered a randomized, placebo-controlled, double-blind clinical trial of oral dextroamphetamine (d-AMP) as a replacement therapy for MA dependence. The subjects took 60 mg sustained-release d-AMP for 8 weeks, during which time they received eight 50-min sessions of individual psychotherapy. Adverse events and urine toxicology for MA were assessed two times a week. There were no serious adverse events. Urine samples containing <1,000 ng/ml of MA were classified as negative for MA. The MA-negative scores in the d-AMP group (3.1 ± SD 4.6) were no higher than those in the placebo group (3.3 ± SD 5.3; P > 0.05). However, withdrawal and craving scores were significantly lower in the d-AMP group (P < 0.05 for both). Although subjects taking d-AMP did not reduce their use of MA, the significant reductions observed in withdrawal and craving scores in this group support the need for further exploration of d-AMP as a pharmacologic intervention for MA dependence, possibly at higher doses.