Brain neuroreceptor density and personality traits: towards dimensional biomarkers for psychiatric disorders

Abstract

Positron emission tomography has, for 30 years, been used in numerous case-control studies searching for hypothesized differences in the density of neuroreceptor or transporter proteins in psychiatric disorders such as schizophrenia and depression. In most cases, the results have not been conclusive. One reason could be the sizeable interindividual variability in biochemical markers, which in twin studies have shown to emanate from both environmental and genetic factors, leading to low statistical power for the detection of group effects. On the other hand, the same interindividual variability has served as an opportunity for correlative studies on the biological underpinning of behaviour. Using this approach, a series of studies has linked markers for the dopamine and serotonin system to personality traits associated with psychiatric conditions. Based on increasing evidence for the view that many psychopathological states represent extremes of a continuum rather than distinct categories, this research strategy may lead to new biological insights about the vulnerability to and pathophysiology of major psychiatric disorders.This article is part of the theme issue 'Diverse perspectives on diversity: multi-disciplinary approaches to taxonomies of individual differences'.

Individual structural features constrain the mouse functional connectome

“…We propose that the emergence of individual features in the functional data is, at least partially, driven by the individual's structural connectivity with stable features encoded in the connectome ( Figure 1E). In addition to connectome specificity, other structural data features may drive functional inter-subject variability including foremost regional variance such as synaptic receptor type and density (39), but also methodological variations such as parcellation differences (3). Notwithstanding, we cannot exclude that the variations in hemodynamic response functions (HRF) across animals and brain location affect SC-FC relations, as it has been shown to contribute to individual variability in human FC estimation (40).…”

Relationship of self‐transcendence traits with in vivo dopamine D2/3 receptor availability and functional connectivity: An [18F]fallypride PET and fMRI study

“…Our PET outcome measure is potentially confounded by the generally unknown occupancy by endogenous dopamine (Cumming, ; Laruelle et al, ; Martinez et al, ). Since a given personality trait may reflect the composite effect of multiple genes and epigenetic factors, we note that a correlation between a certain receptor binding site and a personality trait does not mean that the neurotransmitter protein itself has a causal role or is a marker of that personality trait (Farde, Plavén‐Sigray, Borg, & Cervenka, ). We concede that the [ 18 F]fallypride scan duration was shorter than that of previous studies, which might have led to underestimation of BP ND values, especially in the striatum.…”

Diversity in action: exchange of perspectives and reflections on taxonomies of individual differences

“…A number of the contributions in this theme issue are consistent with the National Institute of Mental Health's Research Domain Criteria (RDoC), which seek to understand the development of underlying phenotypes of psychopathology across multiple developmental stages and at multiple levels of analysis, including genetic and neurodevelopmental pathways [12,21,53]. Farde et al [22] described the benefits of examining the biological underpinnings of dimensional traits rather than categorical psychological disorders. Hoyniak et al [28] examined neural correlates of temperamental inhibitory control in toddlers, observing that larger N2 event-related potential amplitudes in a go/no-go task are associated with poorer inhibitory control.…”

“…Factor Analysis and Structural Equation Modelling) are linear methods that facilitate the identification of structures underlying sets of redundant lexical variables. But such methods are inadequate for analysing the nonlinear relationships found in most psychological and physiological processes in which redundancy rarely occurs [12,[20][21][22]. Instead, statistical methods are needed that enable the identification of fluid processes that interact with one another in a contingent, nonlinear, multi-level and feedback manner that still presents profound challenges for their mathematical formalization [8,10,13].…”

“…R. Soc. B 373: 20170172 control, psychopathy and empathic capacities, verbal abilities, probabilistic thinking, emotional dispositions and sensory processing sensitivity [10,17,[20][21][22][23][25][26][27][28][29][30]. For me, as a clinician, it is intriguing to observe the strong convergence between the lists of traits identified in temperament research and the lists of symptoms of mental disorders as identified in the DSM/ICD (when these traits are expressed in extreme, pathological form; [17,21,23,26,[29][30][31][32][33]).…”