The prestige model of spectrum bipolarity

Abstract

Because affective pathogenesis is a hard problem for psychiatry, it behoves researchers to develop and test novel models of causality. We examine the notion that the adaptive drive to social investment – prestige – provides clues to the bipolar spectrum. A seven node bipolar spectrum is proposed, based on a putative gradient of “bipolarity”. It is conceived that this gradient may correlate with the drive to social investment (prestige). In order to test this hypothesis with proof of concept data, a case control study categorised 228 subjects into a seven node bipolar spectrum. Whilst controlling for mood elevation and depression, differences in strategic prestige (leadership) motivation (MSPM) between spectrum groups were examined. The bipolar I (S1) node had a greater strategic prestige (leadership) motivation score than the controls (S7) by 21.17 points, 95% CI [8.16, 34.18], p < .001, d = 1.05, while the bipolar II (S2) node was higher than the control group by 16.73 points, 95% CI [0.92, 32.54], p = .030, d = 0.84. Whilst the pseudounipolar (S3) node (those with depression and bipolar family histories; n = 17) had only a marginally statistical difference in MSPM compared to controls (p = .051), the mean difference (16.98) and d value (0.86) indicated an elevated MSPM level. Prestige (leadership) motivation score positively correlated with dimensional lifetime bipolarity (Mood Disorder Questionnaire) score (r_p = 0.47), supporting the spectrum prestige motivation gradient notion. Evidence is presented for a genetic disposition to elevated strategic prestige (leadership) motivation. Sensitivity to Social Inclusion (MSIS), Contingency of Self-Worth (CSW.av) and tension significantly predicted strategic prestige (leadership) motivation (MSPM) score in a multiple regression. – suggesting that a vulnerability of the social self may be a feature of bipolar disorders. The prestige model of spectrum bipolarity offers a new conceptualisation of affective disorders and has received preliminary support.

Introduction

A spectrum is a system in which components are contiguously distributed according to rank – best exemplified by the spread of the wavelengths of light – as induced by refraction through a prism. A cyclothymic-bipolar spectrum was first proposed by Akiskal et al. [1], while Klerman [2] suggested a mania spectrum. Ghaemi et al. [3] incepted a model of bipolar spectrum disorder, which bridges the gulf between bipolar I disorder and major depressive disorder. In a fully dimensional spectrum as practiced at Harvard [4], varying degrees of bipolarity are represented. Phelps et al. [5] conceived a revised DSM system, which may conceivably incorporate the bipolar spectrum approach, but equally maintain categories. Can, therefore, an aetiological substrate for the bipolar spectrum be described and can differences in spectrum nodes be established?

Prestige refers to the capacity of the group to invest in the individual [6]. In evolutionary time marginalisation was a survival risk and prestige predicated social inclusion and fitness. Behaviours such as narrative-making, prosodic speech, social engagement, gesture, creativity and mood elevation enhance prestige through object approach – it is noteworthy that these are behaviours inherent to hypomania [7]. Depressive social withdrawal, on the other hand, may be seen as an abrogation of prestige – an attempt at stealth – so as to avoid ostracism [7], comparable to the social risk hypothesis of Allen and Badcock [8]. It is argued that the prototypes of affective interpersonal approach and withdrawal were selected for in ancestral contexts because they enhanced fitness when individual social inclusion was threatened. In turn, the “byproduct” [9] dispositions to more severe, psychotic, and non-adaptive mania and melancholia were “carried along” with their concomitant adaptations.

The present study introduces the concept of social investment (prestige) as a prime driver in the emergence of bipolar spectrum disorders. It provides a structural model for a bipolar spectrum, based on clinical and genetic gradients – suggesting the functional basis for each category. The prestige model of spectrum bipolarity predicts that persons with high bipolarity will have a higher disposition to prestige (leadership) motivation (MSPM) than controls. This is based on the hypothesis that hypomanic and depressive behaviours have co-evolved with this disposition.