Neurobiological trait abnormalities in bipolar disorder

Dissecting trait neurobiological abnormalities in bipolar disorder ( BD) from those characterizing episodes of mood disturbance will help elucidate the aetiopathogenesis of the illness. This selective review highlights the immunological, neuroendocrinological, molecular biological and neuroimaging abnormalities characteristic of BD, with a focus on those likely to reflect trait abnormalities by virtue of their presence in euthymic patients or in unaffected relatives of patients at high genetic liability for illness. Trait neurobiological abnormalities of BD include heightened pro-inflammatory function and hypothalamic-pituitary-adrenal axis dysfunction. Dysfunction in the intracellular signal transduction pathway is indicated by elevated protein kinase A activity and altered intracellular calcium signalling. Consistent neuroimaging abnormalities include the presence of ventricular enlargement and white matter abnormalities in patients with BD, which may represent intermediate phenotypes of illness. In addition, spectroscopy studies indicate reduced prefrontal cerebral N-acetylaspartate and phosphomonoester concentrations. Functional neuroimaging studies of euthymic patients implicate inherently impaired neural networks subserving emotional regulation, including anterior limbic, ventral and dorsal prefrontal regions. Despite heterogeneous samples and conflicting findings pervading the literature, there is accumulating evidence for the existence of neurobiological trait abnormalities in BD at various scales of investigation. The aetiopathogenesis of BD will be better elucidated by future clinical research studies, which investigate larger and more homogenous samples and employ a longitudinal design to dissect neurobiological abnormalities that are underlying traits of the illness from those related to episodes of mood exacerbation or pharmacological treatment. Molecular Psychiatry (2009) 14, 833-846; doi:10.1038/mp.2009.39; published online 19 May 200

Neurobiologia do transtorno de humor bipolar e tomada de decisão na abordagem psicofarmacológica

O Transtorno do Humor Bipolar (THB) caracteriza-se por oscilações do humor que causam prejuízos significativos no âmbito biopsicossocial. O interesse da comunidade científica por este transtorno vem aumentando nos últimos cinco anos em função de sua crescente prevalência associada ao refinamento diagnóstico, à ampliação do arsenal terapêutico e ao conhecimento dos avanços nas pesquisas da neurobiologia do transtorno. A presente revisão aborda questões diagnosticas e terapêuticas aplicadas à neurobiologia dos THB, relacionando-as diretamente à terapêutica dos quadros de mania, hipomania, estados mistos, depressão bipolar e ciclagem rápida, da infância à idade adulta. São revisados criticamente importantes estudos realizados com diferentes fármacos potencialmente eficazes como estabilizadores do humor, nos diversos subdiagnósticos do THB. São analisados fármacos, tais como o lítio, anticonvulsivantes, antipsicóticos, benzodiazepínicos, bloqueadores dos canais de cálcio e hormônio tireoideo, bem como as possíveis bases biológicas para seus efeitos terapêuticos. Em síntese, este trabalho aborda os avanços da psicofarmacologia cuja eficácia é comprovada nos subtipos do THB, procurando relacioná-los com a neurobiologia deste transtorno.Bipolar Disorder (BD) is characterized by mood swings that cause significant impairment in social, occupational, or other areas of functioning. During the last years, new insights have been provided in the diagnosis, etiology, neurobiological basis and treatment of bipolar disorder. This paper emphasizes recent studies related to some diagnostic and therapeutic aspects during manic episode, hypomanic, mixed episode, bipolar depression and rapid cycling, in children, adolescents and adults. Studies using proposed mood stabilizers, which present adequate metodological basis, including double–blind, controlled studies and which presented a significant number of patients were included and critically evaluated in this revision. Drugs such as the lithium, anticonvulsants, antipsychotics, benzodiazepines, calcium channels blockers and thyroid augmentation are proposed to be effective in certain diagnostic profiles. The possible biological bases for these drugs therapeutic effects are also revised. In summary, this article focuses on recent and important psychopharmacological progresses on the treatment of BD subtypes. Furthermore, the revision presents possible biological basis to explain the therapeutic profile of these drugs