Functional Ensemble of Temperament

In this sense temperament (as neuro-chemically-based individual differences) and mental illness represents varying degrees along the same continuum of neurotransmitter imbalance in neurophysiological systems of behavioural regulation.

[1][2][3][4][5][6][7][8][9][10][11] In fact, multiple temperament traits (such as Impulsivity, sensation seeking, neuroticism, endurance, plasticity, sociability or extraversion) have been linked to brain neurotransmitters and hormone systems.

[16] Trevor Robbins, Cambridge University who collaborated with Trofimova on this project in 2014–2016 suggested a revision of the part of the FET neurochemical hypothesis related to the trait of Intellectual (mental) Endurance (known in cognitive psychology also as "sustained attention").

[19] The final STQ-77/FET framework classifies temperament traits and their neurochemical biomarkers into 12 components: nine components regulating the formal functional aspects of behaviour (energetic, dynamic and orientational) each assessed in three domains (intellectual, physical and social-verbal); also three components related to emotionality (Neuroticism, Impulsivity and Satisfaction (Self-Confidence)) (see Figure) [19][34][33][36] The FET framework summarized existing literature showing the nine non-emotionality traits are regulated by the monoamines (MA) (noradrenalin, dopamine, serotonin), acetylcholine and neuropeptide systems, whereas the three emotionality-related traits emerge as a dysregulation of opioid receptors systems that have direct control over MA systems.

[16][17][31][32][19] The FET framework is based only on the strongest consensus points in the research studying the role of neurotransmitter in behavioural regulation and the components of temperament; it doesn't list more controversial links between these multiple systems.

[37][38][39] The interplay within hormonal systems and its interaction with serotonin also appeared to be a factor is social emotions, such as shame and guilt [40] FET framework was proposed to simplify classifications of psychiatric disorders (DSM, ICD) using 12 functional aspects of behaviour that this model highlights.

[9][8][11] FET-developers suggested that every symptom in DSM/ICD diagnoses can be mapped into a specific FET code reflecting a disregulation within well-documented neurochemical systems.