Thyroid Hormone Augmentation for Bipolar Disorder: A Systematic Review

Cognition and gut microbiota in schizophrenia spectrum and mood disorders: A systematic review

FRILEUX, M., BOLTRI M. and al. Cognition and Gut microbiota in schizophrenia spectrum and mood disorders: a Systematic Review. NEUROSCI BIOBEHAV REV (1) 2024 Schizophrenia spectrum disorders and major mood disorders are associated with cognitive impairments. Recent studies suggest a link between gut microbiota composition and cognitive functioning. Here, we review the relationship between gut microbiota and cognition in these disorders. To do this, we conducted a systematic review, searching Cochrane Central Register of Controlled Trials, EBSCOhost, Embase, Pubmed, Scopus, and Web of Science. Studies were included if they investigated the relationship between gut microbiota composition and cognitive function through neuropsychological assessments in patients with bipolar, depressive, schizophrenia spectrum, and other psychotic disorders. Ten studies were identified. Findings underscore a link between gut dysbiosis and cognitive impairment. This relationship identified specific taxa (Haemophilus, Bacteroides, and Alistipes) as potential contributors to bolstered cognitive performance. Conversely, Candida albicans, Toxoplasma gondii, Streptococcus and Deinococcus were associated with diminished performance on cognitive assessments. Prebiotics and probiotics interventions were associated with cognitive enhancements, particularly executive functions. These results emphasize the role of gut microbiota in cognition, prompting further exploration of the underlying mechanisms paving the way toward precision psychiatry.

Current Status and Treatment of Rapid Cycling Bipolar Disorder

BACKGROUND

Rapid cycling (RC) at least 4 recurrent episodes per year in bipolar disorder (BD) has been recognized since the 1970s. We now comment on our recent review of the topic and extensive RC analysis in a large clinical cohort, emphasizing therapeutics research.

COMMENTS

Prevalence of RC-BD averages 36% for any year versus 22% in the preceding year. Rapid cycling is not a consistent feature over many years, although average long-term, annual recurrence rates are greater in RC-BD patients. Risk of RC may be somewhat greater among women and with older ages. It is also associated with cyclothymic temperament, prominent depression, and mood-switching with antidepressant treatment and is associated with increased suicidal risk. Treatment of individual episodes in RC-BD and effective long-term prevention remain inadequately studied, although antidepressant treatment can worsen RC. Some research supports treatment with aripiprazole, lamotrigine, and lithium, and interest in second-generation antipsychotics is emerging. All such options are used in various inadequately evaluated combinations.

CONCLUSIONS

Rapid cycling is prevalent among BD patients but seems to vary in risk over time without evidence of progressive worsening. Treatment of acute episodes in RC-BD patients and effective long-term preventive management require much more intensive investigation.

Collecting Contributions for a Critical Issue: Progressing from Bench to Bedside in Bipolar Disorders

It was a joy reading the submissions for the Brain Sciences Special Issue that I edited, entitled "Bipolar Disorders: Progressing from Bench to Bedside" [...].

Hypokalemic Hypophosphatemic Thyrotoxic Periodic Paralysis Associated with Bipolar Disorder Therapy

Hypokalemic thyrotoxic periodic paralysis (TPP) is a rare complication of hyperthyroidism. TPP occurs due to the intracellular shift of potassium in the setting of elevated thyroid hormone. As potassium begins to be replenished, there is a risk of inducing hyperkalemia due to the extracellular shift of potassium. Therefore, it is recommended to replete potassium conservatively. There have been a number of studies reviewing the possible benefits of elevated thyroid hormone in treating bipolar disorder. In this case report, a 37-year-old man with a past medical history of hypothyroidism and bipolar disorder presented with bilateral lower extremity paralysis. Liothyronine was added to his stable hypothyroid regimen for bipolar management. His initial labs on presentation were notable for severe hypokalemia, hypophosphatemia, and an undetectable thyroid-stimulating hormone (TSH). He was diagnosed with TPP, and his electrolytes were corrected with minimal repletion within 24 hours. More research is still required before concluding the role of thyroid hormone in mood disorders. This case report demonstrates a serious complication of supplemental thyroid hormone use. It is crucial to monitor thyroid function tests closely in order to avoid iatrogenic hyperthyroidism.

Long-Term Lithium Therapy and Thyroid Disorders in Bipolar Disorder: A Historical Cohort Study

Lithium has been a cornerstone treatment for bipolar disorder (BD). Despite descriptions in the literature regarding associations between long-term lithium therapy (LTLT) and development of a thyroid disorder (overt/subclinical hypo/hyperthyroidism, thyroid nodule, and goiter) in BD, factors such as time to onset of thyroid abnormalities and impact on clinical outcomes in the course of illness have not been fully characterized. In this study we aimed to compare clinical characteristics of adult BD patients with and without thyroid disorders who were on LTLT. We aimed to identify the incidence of thyroid disorders in patients with BD on LTLT and response to lithium between patients with and without thyroid disorders in BD. The Cox proportional model was used to find the median time to the development of a thyroid disorder. Our results showed that up to 32% of patients with BD on LTLT developed a thyroid disorder, of which 79% developed hypothyroidism, which was corrected with thyroid hormone replacement. We did not find significant differences in lithium response between patients with or without thyroid disorders in BD. Findings from this study suggest that patients with BD and comorbid thyroid disorders when adequately treated have a response to lithium similar to patients with BD and no thyroid disorders.

Treatment-Resistant Bipolar Depression: Therapeutic Trends, Challenges and Future Directions

INTRODUCTION

Bipolar disorder (BD) is a chronic mental illness impacting 1-2% of the population worldwide and causing high rates of functional impairment. Patients with BD spend most of their time in depressive episodes and up to one-third of patients do not respond to adequate doses of medications. Although no consensus exists for definition of treatment-resistant bipolar depression (TRBD), failure of symptoms improvement despite an adequate trial of two therapeutic agents is a common theme of TRBD. In this paper, we review the evidence base of therapeutic interventions, challenges, and potential future directions for TRBD.

METHODS

We conducted a literature search for randomized controlled trials on PubMed for the treatment of TRBD and ongoing trials for the treatment of TRBD/bipolar depression on clinicaltrials.gov.

RESULTS

Several therapeutic agents have been investigated for TRBD. Adjunctive pramipexole and modafinil have data supporting short-term efficacy in TRBD, along with limited data for racemic intravenous ketamine. Celecoxib augmentation of escitalopram and treatment with metformin in patients with insulin resistance showed promising results. Right unilateral electroconvulsive therapy displayed statistically significant response rate and improvement, but not remission compared to pharmacotherapy. Trials for transcranial magnetic stimulation (TMS) have failed to show a significant difference from sham treatment in TRBD.

FUTURE TRENDS

Pharmacological treatments with novel mechanisms of actions like brexpiprazole and vortioxetine are being investigated following successes in unipolar depression. Modified TMS protocols such as accelerated TMS are under investigation. Innovative approaches like psychedelic-assisted psychotherapy, interleukin-2, fecal microbiota transplantation and multipotent stromal cells are being studied.

CONCLUSION

Evidence on current treatment modalities for TRBD is limited with low efficacy. More research is needed for successful treatment of TRBD. Effective therapies and innovative approaches to treatment are being investigated and could show promise.