Serotonin depletion amplifies distinct human social emotions as a function of individual differences in personality

Abstract

Serotonin is involved in a wide range of mental capacities essential for navigating the social world, including emotion and impulse control. Much recent work on serotonin and social functioning has focused on decision-making. Here we investigated the influence of serotonin on human emotional reactions to social conflict. We used a novel computerised task that required mentally simulating social situations involving unjust harm and found that depleting the serotonin precursor tryptophan—in a double-blind randomised placebo-controlled design—enhanced emotional responses to the scenarios in a large sample of healthy volunteers (n = 73), and interacted with individual differences in trait personality to produce distinctive human emotions. Whereas guilt was preferentially elevated in highly empathic participants, annoyance was potentiated in those high in trait psychopathy, with medium to large effect sizes. Our findings show how individual differences in personality, when combined with fluctuations of serotonin, may produce diverse emotional phenotypes. This has implications for understanding vulnerability to psychopathology, determining who may be more sensitive to serotonin-modulating treatments, and casts new light on the functions of serotonin in emotional processing.

Baiap3 regulates depressive behaviors in mice via attenuating dense core vesicle trafficking in subsets of prefrontal cortex neurons

“…Neuronal serotonin transmission is believed to have a prominent role at the onset of depression. The regulation of emotions and behaviors by serotonin has been verified through various studies and clinical experiences ( Kanen et al, 2021 ; Wolf et al, 2018 ), but both general and context-dependent upstream mechanisms that regulate serotonin are poorly understood. We here propose Baiap3 as a novel candidate emotion regulator based on our findings that Baiap3 regulates serotonin transmission and depressive behavior in two mouse models of depression.…”

Alcohol, Aggression, and Violence: From Public Health to Neuroscience

“…Aggression is a complex behavior involving interactions between the gene, environment, personality, and physiology (Armstrong et al, 2017 ; Zhang et al, 2017 ; Kanen et al, 2021 ). Dysregulation of serotonin is associated with many psychiatric disorders (Rappek et al, 2018 ; Conio et al, 2020 ; Fanning et al, 2020 ) due to the widespread distribution of serotonergic fibers originating from midbrain raphe nuclei to various other regions (Sharp and Barnes, 2020 ).…”

“…However, the inconsistent findings of serotonin markers in brain imaging studies of alcoholics suggest that comorbidity of AUD with other psychiatric disorders may complicate the serotonin hypothesis in real life. In addition, even individual differences in personality traits determine the types of emotion affected by the depletion of serotonin (Kanen et al, 2021 ).…”

Gestational Tryptophan Fluctuation Underlying Ontogenetic Origin of Neuropsychiatric Disorders

“…Moreover, the trait property makes a difference. Guilt is preferentially elevated in highly empathic participants following ATD intervention, while annoyance is potentiated in participants high in trait psychopathy [51]. Hence, maternal plasma (MP) Trp fluctuation underlies the psychopathology of personality disorders, which may interfere fetal personality development via the maternal-fetal transmission, especially in the premise that personality already starts in the womb [3].…”