Joanna K. Soczynska

Inflammation and the phenomenology, pathophysiology, comorbidity, and treatment of bipolar disorder: a systematic review of the literature.

OBJECTIVE To review extant literature implicating inflammation in the pathophysiology of bipolar disorder. Furthermore, we review evidence regarding the anti-inflammatory actions of mood-stabilizing medication, the putative reciprocal association of inflammation with behavioral parameters and medical burden in bipolar disorder, and the potential role of anti-inflammatory agents in the treatment of bipolar disorder. DATA SOURCES MEDLINE and PubMed searches were conducted of English-language articles published from 1950 to April 2008 using the search terms bipolar disorder, manic, or mania, cross-referenced with inflammation, inflammatory, interleukin, cytokine, C-reactive protein, or tumor necrosis factor. The search, which was conducted most recently on August 20, 2008, was supplemented by manually reviewing reference lists from the identified publications. STUDY SELECTION Articles selected for review were based on adequacy of sample size, the use of standardized experimental procedures, validated assessment measures, and overall manuscript quality. DATA EXTRACTION Studies were reviewed for statistical comparisons of cytokines among persons with and without bipolar disorder, during symptomatic and non-symptomatic intervals and before and after pharmacologic treatment. Significant and nonsignificant findings were tabulated. DATA SYNTHESIS Available evidence indicates that bipolar disorder and inflammation are linked through shared genetic polymorphisms and gene expression as well as altered cytokine levels during symptomatic (i.e., mania and depression) and asymptomatic intervals. However, results are inconsistent. Several conventional mood stabilizers have anti-inflammatory properties. The cyclooxygenase-2-selective anti-inflammatory celecoxib may offer antidepressant effects. Inflammation is closely linked with behavioral parameters such as exercise, sleep, alcohol abuse, and smoking, as well as with medical comorbidities including coronary artery disease, obesity and insulin resistance, osteoporosis, and pain. Methodological limitations precluding definitive conclusions are heterogeneity in sample composition, cytokine assessment procedures, and treatment regimens. The inclusion of multiple ethnic groups introduces another source of variability but also increases the generalizability of study findings. CONCLUSION Inflammation appears relevant to bipolar disorder across several important domains. Further research is warranted to parse the reciprocal associations between inflammation and symptoms, comorbidities, and treatments in bipolar disorder. Studies of this topic among youth are needed and may best serve this purpose.

Volumetric neuroimaging investigations in mood disorders: bipolar disorder versus major depressive disorder

BACKGROUND As patients with mood disorders manifest heterogeneity in phenomenology, pathophysiology, etiology, and treatment response, a biological classification of mental disease is urgently needed to advance research. Patient and methodological variability complicates the comparison of neuroimaging study results and limits heuristic model development and a biologically-based diagnostic schema. OBJECTIVE We have critically reviewed and compared the magnetic resonance neuroimaging literature to determine the degree and directionality of volumetric changes in brain regions putatively implicated in the pathophysiology of major depressive disorder (MDD) versus bipolar disorder (BD). METHODS A total of 140 published magnetic resonance imaging investigations evaluating subjects with BD or MDD were selected to provide a summary and interpretation of volumetric neuroimaging results in MDD and BD. Further commentary on the pathophysiological implications, and putative cellular and pharmacological mechanisms, is also provided. RESULTS While whole brain volumes of patients with mood disorders do not differ from those of healthy controls, regional deficits in the frontal lobe, particularly in the anterior cingulate and the orbitofrontal cortex, appear to consistently differentiate subjects with mood disorders from the general population. Preliminary findings also suggest that subcortical structures, particularly the striatum, amygdala, and hippocampus, may be differentially affected in MDD and BD. CONCLUSIONS Structural neuroimaging studies have consistently identified regional abnormalities in subjects with mood disorders. Future studies should strive to definitively establish the influence of age and medication.

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.

The effect of antidepressants on glucose homeostasis and insulin sensitivity: synthesis and mechanisms

Objective: To synthesise results from investigations reporting on the effect of antidepressants on glucose–insulin homeostasis. Method: The authors conducted a MedLine search of all English language articles from 1966 to October 2005 using the keywords: bipolar disorder, major depressive disorder, diabetes mellitus, glucose homeostasis, and the name of each antidepressant that has been indicated for major depression in Canada and the US up to October 2005. The search was supplemented with a manual review of relevant references. Both preclinical and clinical investigations were reviewed. Results: Some serotonergic antidepressants (e.g., fluoxetine) reduce hyperglycaemia, normalise glucose homeostasis and increase insulin sensitivity, whereas some noradrenergic antidepressants (e.g., desipramine) exert opposite effects. Dual-mechanism antidepressants (e.g., duloxetine and venlafaxine) do not appear to disrupt glucose homeostatic dynamics, whereas nonselective hydrazine monoamine oxidase inhibitors (e.g., phenelzine) are associated with hypoglycaemia and an increased glucose disposal rate. Conclusion: Some antidepressants exert a clinically significant effect on metabolism relevant to both therapeutic outcome and adverse events.

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.

Medical comorbidity in bipolar disorder: reprioritizing unmet needs

Purpose of review The aim of this review is to synthesize results from extant investigations which report on the co-occurrence of bipolar disorder and medical comorbidity. Recent findings We conducted a MEDLINE search of all English-language articles published between January 2004 and November 2006. Most studies report on medical comorbidity in bipolar samples; relatively fewer studies report the reciprocal association. Individuals with bipolar disorder are differentially affected by several ‘stress-sensitive’ medical disorders notably circulatory disorders, obesity and diabetes mellitus. Neurological disorders (e.g. migraine), respiratory disorders and infectious diseases are also prevalent. Although relatively few studies have scrutinized the co-occurrence of bipolar disorder in medical settings, individuals with epilepsy, multiple sclerosis, migraine and circulatory disorders may have a higher prevalence of bipolar disorder. A clustering of traditional and emerging (e.g. immunoinflammatory activation) risk factors presage somatic health issues in the bipolar disorder population. Iatrogenic factors and insufficient access to primary, preventive and integrated healthcare systems are also contributory. Summary Somatic health issues in individuals with bipolar disorder are ubiquitous, under-recognized and suboptimally treated. Facile screening for risk factors and laboratory abnormalities along with behavioral modification for reducing medical comorbidity are warranted.

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 prevalence and impact of migraine headache in bipolar disorder: results from the Canadian Community Health Survey.

Objective.—To report on the prevalence of comorbid migraine in bipolar disorder and the implications for bipolar age of onset, psychiatric comorbidity, illness course, functional outcome, and medical service utilization.

Novel therapeutic targets in depression: Minocycline as a candidate treatment

Mood disorders are marked by high rates of non-recovery, recurrence, and chronicity, which are insufficiently addressed by current therapies. Several patho-etiological models have been proposed that are not mutually exclusive and include but are not limited to the monoamine, inflammatory, neurotrophic, gliotrophic, excitatory, and oxidative stress systems. A derivative of these observations is that treatment(s) which target one or more of these mechanistic steps may be capable of mitigating, or preventing, disparate psychopathological features. Minocycline is an agent with pleiotropic properties that targets multiple proteins and cellular processes implicated in the patho-etiology of mood disorders. Moreover, preclinical and preliminary clinical evidence suggests that minocycline possesses antidepressant properties. Herein, we provide the rationale for conducting a randomized, controlled trial to test the antidepressant properties of minocycline.

Towards a multifactorial approach for prediction of bipolar disorder in at risk populations

BACKGROUND The high prevalence, recurrence rate, chronicity, and illness burden in bipolar disorder (BD) are well documented. Moreover, insufficient response with conventional pharmacological and manual-based psychosocial interventions, as well as evidence of illness progression and acceleration, invite the need for early detection and primary prevention. METHODS Herein we comprehensively review extant studies reporting on a bipolar prodrome. The overarching aim is to propose a predictive algorithm (i.e. prediction of BD in at-risk populations) integrating genetic (i.e. family history), environmental (e.g. childhood maltreatment) and biological markers (i.e. BDNF, inflammatory and oxidative stress markers). Computerized databases i.e. Pubmed, PsychInfo, Cochrane Library and Scielo were searched using the followed terms: bipolar disorder cross-referenced with prodromal, preclinical, at risk mental states, clinical high risk, ultra high risk, biomarkers, brain-derived neurotrophic factor, inflammation, cytokines, oxidative stress, prediction and predictive model. RESULTS Available evidence indicates that a prodrome to bipolar disorder exists. Commonly encountered features preceding the onset of a manic episode are affective lability, irritability, anger, depression, anxiety, substance use disorders, sleep disorders, as well as disturbances in attention and cognition. Non-specificity and insufficient sensitivity have hampered the development of an adequate prediction algorithm. LIMITATIONS Limitations include biases associated with retrospective studies, poor characterization of clinical high risk, inadequacy of prospective studies regarding sample selection and absence of specificity of risk states. CONCLUSION We propose a hypothetical prediction algorithm that is combinatorial in approach that attempts to integrate family history, early adversity, and selected biomarkers.