Mohammad Alsuwaidan

COGNITIVE DEFICITS AND FUNCTIONAL OUTCOMES IN MAJOR DEPRESSIVE DISORDER: DETERMINANTS, SUBSTRATES, AND TREATMENT INTERVENTIONS

Few reports have aimed to describe the mediational effect of cognitive deficits on functional outcomes in major depressive disorder (MDD), and relatively few interventions are demonstrated to mitigate cognitive deficits in MDD.

Bipolar disorder and metabolic syndrome: an international perspective.

INTRODUCTION The ubiquity and hazards posed by abnormal body composition and metabolic parameters in the bipolar population are a priority research and clinical issue. Herein, we summarize and synthesize international studies describing the rate of US National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III [ATP III])- and International Diabetes Federation (IDF)-defined metabolic syndrome and its criterion components in individuals with bipolar disorder. METHODS We conducted a PubMed search of all English-language articles published between January 2005 and July 2009 with the following search terms: metabolic syndrome and bipolar disorder, mania and manic-depression. Articles selected for review were based on adequacy of sample size, the use of standardized experimental procedures, validated assessment measures, and overall manuscript quality. RESULTS The rate of metabolic syndrome in individuals with bipolar disorder is increased relative to the general population. Disparate estimates are reported ranging from comparability to approximately twofold greater than the general population. The increased hazard for metabolic syndrome amongst bipolar individuals is now documented in twelve countries from Europe, Australia, Asia, North and South America. The co-occurrence of metabolic syndrome in the bipolar population is associated with a more complex illness presentation, less favourable response to treatment, and adverse course and outcome. The association between metabolic syndrome and bipolar disorder is mediated/moderated by both iatrogenic and non-iatrogenic factors. DISCUSSION The increased hazard for metabolic syndrome in bipolar populations is due to the clustering of traditional (and emerging) risk factors as well as iatrogenic and health systems factors. Extant data support recommendations for prioritizing, surveillance, prevention, diagnosis and management of metabolic syndrome as routine care of the bipolar patient.

Mood Disorders and Obesity: Understanding Inflammation as a Pathophysiological Nexus

The aim of this review is to evaluate the evidentiary base supporting the hypothesis that the increased hazard for obesity in mood disorder populations (and vice versa) is a consequence of shared pathophysiological pathways. We conducted a PubMed search of all English-language articles with the following search terms: obesity, inflammation, hypothalamic-pituitary-adrenal axis, insulin, cognition, CNS, and neurotransmitters, cross-referenced with major depressive disorder and bipolar disorder. The frequent co-occurrence of mood disorders and obesity may be characterized by interconnected pathophysiology. Both conditions are marked by structural and functional abnormalities in multiple cortical and subcortical brain regions that subserve cognitive and/or affective processing. Abnormalities in several interacting biological networks (e.g. immuno-inflammatory, insulin signaling, and counterregulatory hormones) contribute to the co-occurence of mood disorders and obesity. Unequivocal evidence now indicates that obesity and mood disorders are chronic low-grade pro-inflammatory states that result in a gradual accumulation of allostatic load. Abnormalities in key effector proteins of the pro-inflammatory cascade include, but are not limited to, cytokines/adipokines such as adiponectin, leptin, and resistin as well as tumor necrosis factor alpha and interleukin-6. Taken together, the bidirectional relationship between obesity and mood disorders may represent an exophenotypic manifestation of aberrant neural and inflammatory networks. The clinical implications of these observations are that, practitioners should screen individuals with obesity for the presence of clinically significant depressive symptoms (and vice versa). This clinical recommendation is amplified in individuals presenting with biochemical indicators of insulin resistance and other concurrent conditions associated with abnormal inflammatory signaling (e.g. cardiovascular disease).

The Association between Conventional Antidepressants and the Metabolic Syndrome A Review of the Evidence and Clinical Implications

Major depressive disorder is a prevalent recurrent medical syndrome associated with inter-episodic dysfunction. The metabolic syndrome is comprised of several established risk factors for cardiovascular disease (i.e. abdominal obesity, dyslipidaemia, dysglycaemia and hypertension). The criterion items of the metabolic syndrome collectively represent a multi-dimensional risk factor for cardiovascular disease and type 2 diabetes mellitus. Extant evidence indicates that both major depressive disorder and the metabolic syndrome, albeit distinct, often co-occur and are possibly subserved by overlapping pathophysiology and causative mechanisms. Conventional antidepressants exert variable effects on constituent elements of the metabolic syndrome, inviting the need for careful consideration prior to treatment selection and sequencing. Initiating and maintaining antidepressant therapy should include routine surveillance for clinical and/or biochemical evidence suggestive of the metabolic syndrome.

A preclinical and clinical rationale for quetiapine in mood syndromes

The main objective of this review is to discuss results from preclinical studies that aim to elucidate the putative mechanistic basis of the antidepressant action of quetiapine. Results from pivotal, randomized clinical trials in bipolar depression are also briefly reviewed. The authors conducted a PubMed search of all English-language articles published between January 1990 and December 2006. The key search term was quetiapine paired with: serotonin, dopamine, noradrenaline, glutamate, γ-aminobutyric acid, signal transduction, neurogenesis, oxidative stress, glucocorticoid, antidepressant, major depressive disorder, bipolar disorder and randomized controlled trial. The search was augmented with a manual review of relevant article reference lists. Articles selected for review were based on author consensus, adequacy of sample size, the use of standardized experimental procedures, validated assessment measures and overall manuscript quality. Quetiapine enhances central serotonergic neurotransmission via its high affinity for serotonergic receptors (e.g., 5-HT2A receptor antagonism and partial agonistic activity at the 5-HT1A receptor). Activation of the 5HT1A receptor results in an increase in prefrontal cortex dopaminergic neurotransmission. Affinity for the α2-adrenoceptor mediates a relative increase in extracellular noradrenergic release in the prefrontal cortex. Emerging evidence indicates that quetiapines principal, active, human plasma metabolite, N-desalkyl quetiapine, has high affinity for, and is a potent inhibitor of, the noradrenergic transporter. This latter finding is a point of commonality with other conventional antidepressant agents and may differentiate quetiapine from other atypical antipsychotics. Activity at other intracellular targets (e.g., signal transduction pathways and nerve growth transcription factors), neurotransmitters, inflammatory and oxidative stress networks, and endocrine systems may also mediate the antidepressant effects of quetiapine. The in vitro pharmacodynamic profile of quetiapine is predictive of antidepressant activity in mood syndromes. Available clinical evidence has established quetiapine as an effective monotherapy in bipolar depression.

Cracks and crevices: Globalization discourse and medical education

Globalization discourse, and its promises of a ‘flat world’, ‘borderless economy’ and ‘mobility of ideas and people’, has become very widespread in all fields. In medical education this discourse is underpinned by assumptions that medical competence has universal elements and that medical education can therefore develop ‘global standards’ for accreditation, curricula and examinations. Yet writers in the field other than medicine have raised a number of concerns about an overemphasis on the economic aspects of globalization. This article explores the notion that it is time to study and embrace differences and discontinuities in goals, practices and values that underpin medical competence in different countries and to critically examine the promises–realized or broken–of globalization discourse in medical education.

The neuroprotective effects of GLP-1: possible treatments for cognitive deficits in individuals with mood disorders.

Incretins are a group of gastrointestinal hormones detected both peripherally and in the central nervous system (CNS). Recent studies have documented multiple effects of incretins on brain structure and function. Research into the neurological effects of incretins has primarily focused on animal models of neurodegenerative disorders (e.g., Alzheimers Disease, Huntingtons and Parkinsons diseases). Mood disorders (e.g. bipolar disorder (BD), major depressive disorder (MDD)) are associated with similar alterations in brain structure and function, as well as a range of cognitive deficits (e.g. memory, learning, executive function). Brain abnormalities and cognitive deficits are also found in populations with metabolic disorders (e.g., diabetes mellitus Type 2). In addition, individuals with mood disorders often have co-morbid metabolic conditions, thus treatment strategies which can effectively treat both cognitive deficits and metabolic abnormalities represent a possible integrated treatment avenue. In particular, glucagon-like peptide-1 (GLP-1) and its more stable, longer-lasting analogues have been demonstrated to exert neuroprotective and anti-apoptotic effects, reduce beta-amyloid (Aβ) plaque accumulation, modulate long-term potentiation and synaptic plasticity, and promote differentiation of neuronal progenitor cells. In animal models of behaviour, treatment with GLP-1 receptor agonists has been demonstrated to improve measures of cognitive function including learning and memory, as well as reduce depressive behaviour. Available GLP-1 treatments also have a favourable metabolic profile which includes weight loss and reduced risk for hypoglycemia. Systematic evaluation of the effects of GLP-1 treatment in psychiatric populations who evince cognitive deficits represents a promising treatment avenue.

The impact of cognitive impairment on perceived workforce performance: Results from the International Mood Disorders Collaborative Project

BACKGROUND Cognitive dysfunction and depression severity are key mediators of workplace adjustment in adults with major depressive disorder (MDD). Herein, we sought to determine the extent to which measures of depression severity and cognitive dysfunction were associated with perceived global disability, workplace performance and quality of life. METHOD A post hoc analysis was conducted using data from 260 participants with a diagnosis of DSM-IV-TR-defined MDD who were enrolled in the International Mood Disorders Collaborative Project (IMDCP) between January 2008 and July 2013. Measures of workplace function, global disability, depression severity, cognitive function, and quality of life were employed. These data were analyzed using a multiple variable linear regression equations. RESULTS Perceived global disability was significantly predicted by clinical ratings of depression severity (β=0.54), and perceived inattention (β=0.24), accounting for 37% of the variance. In addition, perceived inattention (β=0.58) and clinical ratings of depression severity (β=0.18), were also significant predictors of perceived workplace productivity/performance, accounting for 38% of the variance. Finally, both clinical ratings of depression severity (β=-0.54), and perceived inattention (β=-0.18) were significant inverse predictors of perceived quality of life, accounting for 34% of the variance. CONCLUSION The overarching finding in the analysis herein is that workplace performance variability is explained by subjective measures of cognitive dysfunction to a greater extent than total depression symptom severity. Conversely, total depression symptom severity accounts for a greater degree of variability in global measures of disability relative to cognitive measures. Treatment strategies for adults with major depressive disorder should address issues of cognitive dysfunction to improve workforce participation and performance.

Brain Volume Abnormalities and Neurocognitive Deficits in Diabetes Mellitus: Points of Pathophysiological Commonality with Mood Disorders?

BackgroundIt is hypothesized that diabetes mellitus (DM) and mood disorders share points of pathophysiological commonality in the central nervous system.MethodsA PubMed search of all English-language articles published between 1966 and March 2009 was performed with the following search terms: depression, mood disorders, hippocampus, amygdala, central nervous system, brain, neuroimaging, volumetric, morphometric, and neurocognitive deficits, cross-referenced with DM. Articles selected for review were based on adequacy of sample size, the use of standardized experimental procedures, validated assessment measures, and overall manuscript quality. The primary author was principally responsible for adjudicating the merit of articles that were included.ResultsVolumetric studies indicate that individuals with Type 1/2 DM exhibit regional abnormalities in both cortical and subcortical (eg, hippocampus, amygdala) brain structures. The pattern of neurocognitive deficits documented in individuals with Type 1 DM overlap with Type 2 populations, with suggestions of discrete abnormalities unique to each phenotype. The pattern of volumetric and neurocognitive deficits in diabetic populations are highly similar to that reported in populations of individuals with major depressive disorder.ConclusionThe prevailing models of disease pathophysiology in DM and major depressive disorder are distinct. Notwithstanding, the common abnormalities observed in disparate effector systems (eg, insulin resistance, immunoinflammatory activation) as well as brain volume and neurocognitive performance provide the nexus for hypothesizing that both conditions are subserved by overlapping pathophysiology. This conception provides a novel framework for disease modeling and treatment development in mood disorder.

The hepatic safety profile of duloxetine: a review.

Background: Hepatotoxicity related to the use of duloxetine resulted in rewording of the US product insert. Objective: To characterize the hepatic safety profile of duloxetine. Methods: We conducted a PubMed search of all English-language articles published between January 1990 and December 2007 and contacted the manufacturer (Eli Lilly, Inc.). Results: Elevations of alanine aminotransferase to three times the upper limit of normal occurs in 0.9 – 1.7% of duloxetine-treated patients versus 0.0 – 0.3% of placebo-treated patients. Hepatocellular, cholestatic and mixed hepatocellular-cholestatic forms of hepatic injury have been described. Conclusion: Duloxetine does not appear to pose a greater hazard for hepatic toxicity when compared to other conventional antidepressants. Systematic monitoring of liver aminotransferases does not appear to be warranted with routine duloxetine use.