Assessing the continuum between temperament and affective illness: psychiatric and mathematical perspectives

Abstract

Temperament of healthy people and mental illnesses, particularly affective disorders, have been conjectured to lie along a continuum of neurobehavioural regulation. Understanding the nature of this continuum may better inform the construction of taxonomies for both categories of behaviour. Both temperament and mental illness refer to patterns of behaviour that manifest over long time scales (weeks to years) and they appear to share many underlying neuroregulatory systems. This continuum is discussed from the perspectives of nonlinear dynamical systems theory, neurobiology and psychiatry as applied to understanding such multiscale time-series behaviour. Particular emphasis is given to issues of generativity, fungibility, metastability, non-stationarity and contextuality. Implications of these dynamical properties for the development of taxonomies will be discussed. Problems with the over-reliance of psychologists on statistical and mathematical methods in deriving their taxonomies (particularly those based on factor analysis) will be discussed from a dynamical perspective. An alternative approach to temperament based upon functionality, and its discriminative capabilities in mental illness, is presented.This article is part of the theme issue ‘Diverse perspectives on diversity: multi-disciplinary approaches to taxonomies of individual differences’.

Taxonomies of psychological individual differences: biological perspectives on millennia-long challenges

“…This coincides with presentation of main symptoms of depression as clinical variations in temperament traits of physical endurance (symptom of fatigue), physical tempo (i.e. motor retardation), sociability (social withdrawal), plasticity (apathy for new tasks), sustained attention (inability to focus), impulsivity, confidence (low self-image) and neuroticism (increasing worries) [39,47]. Well-documented associations of these symptoms and traits with actions of specific neurotransmitters, neuropeptides and hormones [3,7,9,10,16,24,39,47] are reported in the extensive field of psycho-pharmacology; genetic associations and links to the dopaminergic systems are also commonly found in schizophrenia research [48,52].…”

“…Models derived from human language therefore cannot constitute models of biologically-based traits as FFM proponents often claim. Instead, they likely represent dimensions of socio-cultural perception and appraisal, as noted by many authors [3,5,16,[26][27][28][29][30][31][32][33][34][35][36][39][40][41]46].…”

“…Age is often important to diagnose medical conditions, including psychiatric problems. Several temperament (neurochemically based) traits that are important for individuals' functioning may be less noticed by society (figure 1) even though, as shown in this theme issue, they have welldocumented biological bases: plasticity and impulsivity [1][2][3]6,23,25,41], sensation seeking [10,25], speed of speech and physical actions [1,7,16,24], sustained attention or effortful control [12], sensory sensitivity [15], psychopathy and empathy [3,8], a system of positive emotionality and security [16,18], physical endurance [1,3,23], which, in its weakness, shows up as a main symptom of depressive dispositions [39,47].…”

“…That is why studies such as those reported here, especially by Netter [7], and Farde et al [10] are so valuable. It is therefore important that we do not squander these resources on explorations of constructs derived from human language but instead use objective methods based on experimental psychology or well-validated questionnaires developed on the basis of findings from biology-rooted sciences such as differential psychophysiology [1,4,9,12,14,15,[23][24][25], psychiatry [8,14,18,39,50] or neurochemistry [3,16,23,24,39,46].…”

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

“…Those papers of the theme issue focusing on ways of taxonomy formation and basic concepts of measurement [10][11][12][13][14] mostly emphasized nonlinearity instead of linear traits, and patterns of phenomena instead of single dimensions required for measurement and taxonomy of temperament. Some of them seem to represent controversial positions like: formation of concepts as a first step and deriving experiments, which fit the model thereafter [10,12], as opposed to others deriving their taxonomies from a data-driven approach [11]. I would like to point out that these approaches are compatible when analysing the basic meanings represented by the term linearity and temperament traits.…”