Does obesity and diabetes mellitus metastasize to the brain? "Metaboptosis" and implications for drug discovery and development

Exploring the mechanisms of action of the antidepressant effect of the ketogenic diet

The ketogenic diet (KD) is characterized by a diet ratio of 4:1 fat to non-fat energy sources. For decades KD has been successfully used to control seizures in epilepsy patients. Investigations into its mechanism of action suggest that it may have an effect on the metabolic, nervous, immune, and digestive systems. In this review, we postulate that KD may also improve depressive symptoms - for that, we highlight the similarities between depression and epilepsy, describe the extent to which body systems involved in both conditions are affected by the KD, and ultimately hypothesize how KD could improve MDD outcomes. Research into animal models and human patients have reported that KD can increase mitochondrial biogenesis and increase cellular resistance to oxidative stress both at the mitochondrial and genetic levels. Its effect on neurotransmitters alters cell-to-cell communication in the brain and may decrease hyperexcitability by increasing Gamma Aminobutyric Acid (GABA) and decreasing excitatory neurotransmitter levels. Its anti-inflammatory effects are mediated by decreasing chemo- and cytokine levels, including TNF-alpha and IL-1 levels. Finally, KD can alter gut microbiota (GM). Certain strains of microbiota predominate in major depressive disorder (MDD) when compared to healthy individuals. Recent evidence points to Bacteroidetes as a potential treatment predictor as it seems to increase in KD treatment responders for epilepsy. Each of these observations contributes to the presumed modulatory effects of KD on mood and supports its potential role as antidepressant.

Psychiatric Safety and Weight Loss Efficacy of Naltrexone/bupropion as Add-on to Antidepressant Therapy in Patients with Obesity or Overweight

There is significant association between obesity and depression. Naltrexone/Bupropion (NB) is indicated for treatment of overweight and obesity (BMI ≥27 kg/m² with a comorbidity or ≥30 kg/m²). This post-hoc analysis examines safety and efficacy of NB and placebo among individuals with overweight or obesity who were also taking antidepressant therapy during the LIGHT trial (N=8910). Subjects were divided into four subgroups: NB + antidepressants (n=1150), NB without antidepressants (n=3300), placebo + antidepressants (n=1127) and placebo without antidepressants (n=3317). Among subjects taking NB, the combined incidence of serious adverse events (AEs) and AEs leading to treatment discontinuation was not significantly different between those on antidepressants and those who were not. The key weight-loss efficacy analyses were performed on NB or placebo-treated subjects who remained on study therapy through 104 weeks and who did or did not have documented antidepressant use at each of the baseline, week 52 and week 104 visits (Completers: N=1811; 47.0% female, 86.9% white, mean age of 61 years, mean baseline BMI 37.4 kg/m²). The mean adjusted weight change in subjects taking antidepressants was numerically, but not significantly greater for NB vs. placebo (-6.3% vs. -4.3%). For those subjects not on antidepressants, weight loss was significantly greater for NB vs. PL (-6.8% vs. -3.6%). NB is generally well tolerated in patients with overweight or obesity who are on antidepressants and is effective in promoting weight loss regardless of antidepressant use. These results show that for patients on antidepressant therapy, NB may be an effective option for obesity management.

Bipolar disorders

Bipolar disorders are a complex group of severe and chronic disorders that includes bipolar I disorder, defined by the presence of a syndromal, manic episode, and bipolar II disorder, defined by the presence of a syndromal, hypomanic episode and a major depressive episode. Bipolar disorders substantially reduce psychosocial functioning and are associated with a loss of approximately 10-20 potential years of life. The mortality gap between populations with bipolar disorders and the general population is principally a result of excess deaths from cardiovascular disease and suicide. Bipolar disorder has a high heritability (approximately 70%). Bipolar disorders share genetic risk alleles with other mental and medical disorders. Bipolar I has a closer genetic association with schizophrenia relative to bipolar II, which has a closer genetic association with major depressive disorder. Although the pathogenesis of bipolar disorders is unknown, implicated processes include disturbances in neuronal-glial plasticity, monoaminergic signalling, inflammatory homoeostasis, cellular metabolic pathways, and mitochondrial function. The high prevalence of childhood maltreatment in people with bipolar disorders and the association between childhood maltreatment and a more complex presentation of bipolar disorder (eg, one including suicidality) highlight the role of adverse environmental exposures on the presentation of bipolar disorders. Although mania defines bipolar I disorder, depressive episodes and symptoms dominate the longitudinal course of, and disproportionately account for morbidity and mortality in, bipolar disorders. Lithium is the gold standard mood-stabilising agent for the treatment of people with bipolar disorders, and has antimanic, antidepressant, and anti-suicide effects. Although antipsychotics are effective in treating mania, few antipsychotics have proven to be effective in bipolar depression. Divalproex and carbamazepine are effective in the treatment of acute mania and lamotrigine is effective at treating and preventing bipolar depression. Antidepressants are widely prescribed for bipolar disorders despite a paucity of compelling evidence for their short-term or long-term efficacy. Moreover, antidepressant prescription in bipolar disorder is associated, in many cases, with mood destabilisation, especially during maintenance treatment. Unfortunately, effective pharmacological treatments for bipolar disorders are not universally available, particularly in low-income and middle-income countries. Targeting medical and psychiatric comorbidity, integrating adjunctive psychosocial treatments, and involving caregivers have been shown to improve health outcomes for people with bipolar disorders. The aim of this Seminar, which is intended mainly for primary care physicians, is to provide an overview of diagnostic, pathogenetic, and treatment considerations in bipolar disorders. Towards the foregoing aim, we review and synthesise evidence on the epidemiology, mechanisms, screening, and treatment of bipolar disorders.