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Ricci A, Idzikowski MA, Soares CN, Brietzke E. Exploring the mechanisms of action of the antidepressant effect of the ketogenic diet. Rev Neurosci 2021; 31:637-648. [PMID: 32406387 DOI: 10.1515/revneuro-2019-0073] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 10/11/2019] [Indexed: 12/19/2022]
Abstract
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.
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Affiliation(s)
- Alessandro Ricci
- Department of Psychiatry, Queen's University School of Medicine, 752 King Street West, K7L7X3, Kingston, ON, Canada
| | - Maia A Idzikowski
- Department of Psychiatry, Queen's University School of Medicine, 752 King Street West, K7L7X3, Kingston, ON, Canada
| | - Claudio N Soares
- Department of Psychiatry, Queen's University School of Medicine, 752 King Street West, K7L7X3, Kingston, ON, Canada.,Providence Care Hospital, Kingston, ON, Canada.,Kingston General Hospital, Kingston, ON, Canada.,Centre for Neuroscience Studies (CNS), Queen's University, Kingston, ON, Canada
| | - Elisa Brietzke
- Department of Psychiatry, Queen's University School of Medicine, 752 King Street West, K7L7X3, Kingston, ON, Canada.,Kingston General Hospital, Kingston, ON, Canada.,Centre for Neuroscience Studies (CNS), Queen's University, Kingston, ON, Canada
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McIntyre RS, Berk M, Brietzke E, Goldstein BI, López-Jaramillo C, Kessing LV, Malhi GS, Nierenberg AA, Rosenblat JD, Majeed A, Vieta E, Vinberg M, Young AH, Mansur RB. Bipolar disorders. Lancet 2020; 396:1841-1856. [PMID: 33278937 DOI: 10.1016/s0140-6736(20)31544-0] [Citation(s) in RCA: 393] [Impact Index Per Article: 98.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 06/11/2020] [Accepted: 07/07/2020] [Indexed: 12/17/2022]
Abstract
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.
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Affiliation(s)
- Roger S McIntyre
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Department of Pharmacology, University of Toronto, Toronto, ON, Canada; Brain and Cognition Discovery Foundation, Toronto, ON, Canada.
| | - Michael Berk
- Institute for Mental and Physical Health and Clinical Translation Strategic Research Centre, School of Medicine, Deakin University, Melbourne, VIC, Australia; Mental Health Drug and Alcohol Services, Barwon Health, Geelong, VIC, Australia; Orygen, The National Centre of Excellence in Youth Mental Health, Melbourne, VIC, Australia; Centre for Youth Mental Health, Florey Institute for Neuroscience and Mental Health, Melbourne, VIC, Australia; Department of Psychiatry, The University of Melbourne, Melbourne, VIC, Australia
| | - Elisa Brietzke
- Department of Psychiatry, Adult Division, Kingston General Hospital, Kingston, ON, Canada; Department of Psychiatry, Queen's University School of Medicine, Queen's University, Kingston, ON, Canada; Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada
| | - Benjamin I Goldstein
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Centre for Youth Bipolar Disorder, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Carlos López-Jaramillo
- Department of Psychiatry, Faculty of Medicine, University of Antioquia, Medellín, Colombia; Mood Disorders Program, Hospital Universitario San Vicente Fundación, Medellín, Colombia
| | - Lars Vedel Kessing
- Copenhagen Affective Disorders Research Centre, Psychiatric Center Copenhagen, Rigshospitalet, Copenhagen, Denmark; Department of Psychiatry, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gin S Malhi
- Discipline of Psychiatry, Northern Clinical School, University of Sydney, Sydney, NSW, Australia; Department of Academic Psychiatry, Northern Sydney Local Health District, Sydney, Australia
| | | | - Joshua D Rosenblat
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Dauten Family Center for Bipolar Treatment Innovation, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Amna Majeed
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada
| | - Eduard Vieta
- Hospital Clinic, Institute of Neuroscience, University of Barcelona, IDIBAPS, CIBERSAM, Barcelona, Spain
| | - Maj Vinberg
- Department of Psychiatry, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Psychiatric Research Unit, Psychiatric Centre North Zealand, Hillerød, Denmark
| | - Allan H Young
- Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London and South London and Maudsley National Health Service Foundation Trust, Bethlem Royal Hospital, London, UK
| | - Rodrigo B Mansur
- Mood Disorders Psychopharmacology Unit, University Health Network, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada
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