Neurobiological Factors Linking Personality Traits and Major Depression

Abstract

R ecent advances in neuroscience have yielded plausible, although partial, explanations for the neurobiological basis of MDD. Here we consider whether recent work in neurobiology can also address the etiologic relation between personality and MDD. First, however, it is fair to acknowledge that there remains a valid question regarding whether neuroscience has advanced to the point that useful comments on the biological underpinnings of complex traits such as personality can be made. Nonetheless, the question has not prevented an abundance of recent reviews that purport to summarize the neurobiology of intelligence, 1 Objective: To examine the neurobiological basis of personality and depression.Method: We examined preclinical and clinical studies related to neuroanatomy, neuroendocrine, molecular, and genetic alterations in depressed patients. We considered whether common neurobiological factors might be shared between personality and depression.Results: Preclinical studies provide insights into the neurobiological mechanisms underlying the pathophysiology of depression including neuroendocrine alterations in hypothalamic-pituitary-adrenal (HPA) function, neuroanatomical alterations in key brain regions, and alterations in neurotrophin and serotonergic signalling systems. Clinical studies show similar alterations in depressed patients. Evidence suggests that neuroendocrine alterations in HPA function may contribute to personality traits. Brain regions implicated in depression, including the hippocampus and the anterior cingulate cortex, might play a role in personality. Key molecules implicated in depression have been extensively studied with reference to personality traits, particularly neuroticism. To date, physiological measures (serum and positron emission tomography) provide the strongest evidence implicating brain-derived neurotrophic factor and serotonin in personality, while genetic evidence is less convincing. Conclusions:A neurobiological link exists between personality and depression; however, more work is needed to provide an understanding of the nature of this relation and to link this work with clinical studies examining the influence of personality factors on depression.Can J Psychiatry 2008;53(1):6-13Information on funding and support and author affiliations appears at the end of the article. Clinical Implications· Neurobiological links exists between personality traits and risk for depression. · Understanding the genetic and molecular basis of personality and depression will allow refinement of our clinical tools and provide novel targets for therapeutic development. Limitation· Differences in experimental design and exclusion criteria make it difficult to compare study results and there are no obvious reasons for discrepancies among reports.

From high anxiety trait to depression: a neurocognitive hypothesis

“…Another important feature in depression is a dysregulation of the hypothalamus-pituitary-adrenocortical (HPA) axis [12]. Many depressed subjects display enhanced cortisol secretion as a consequence of an overactive HPA axis [13], and enhanced activity of corticotropin-releasing-factor (CRF) systems in limbic regions has been related with increased depression-like symptomatology [14].…”

Personality and bipolar disorder: dissecting state and trait associations between mood and personality

“…Associations between personality traits and psychiatric disorders may occur for several reasons, including ' scarring ' of personality by mood episodes, shared genetic risk for personality and disorder, or methodological artifacts such as overlapping items in symptom and personality rating scales (Shea et al 1996 ;Duggan et al 2003 ;Foster & MacQueen, 2008). The relationship between personality and symptoms is particularly complex in BD because personality scores can be affected by mood state (Kendell & DiScipio, 1968 ;Reich et al 1987) and by residual symptoms present even during euthymic states (Katz & McGuffin, 1987 ;Sauer et al 1997).…”

Neural correlates of personality dimensions and affective measures during the anticipation of emotional stimuli

“…Nowadays, neurobiological aspects of personality factors or dimensions may serve as one approach to the neurobiology of and the predisposition for affective disorders (Foster and MacQueen 2008).…”