The serotonin system and spiritual experiences.
OBJECTIVE
The serotonin system has long been of interest in biological models of human personality. The purpose of this positron emission tomography (PET) study was to search for relationships between serotonin 5-HT(1A) receptor density and personality traits.


METHODS
Fifteen normal male subjects, ages 20-45 years, were examined with PET and the radioligand [(11)C]WAY100635. Personality traits were assessed with the Swedish version of the Temperament and Character Inventory self-report questionnaire. Binding potential, an index for the density of available 5-HT(1A) receptors, was calculated for the dorsal raphe nuclei, the hippocampal formation, and the neocortex. For each region, correlation coefficients between 5-HT(1A) receptor binding potential and Temperament and Character Inventory personality dimensions were calculated and analyzed in two-tailed tests for significance.


RESULTS
The authors found that the binding potential correlated inversely with scores for self-transcendence, a personality trait covering religious behavior and attitudes. No correlations were found for any of the other six Temperament and Character Inventory dimensions. The self-transcendence dimension consists of three distinct subscales, and further analysis showed that the subscale for spiritual acceptance correlated significantly with binding potential but not with the other two subscales.


CONCLUSIONS
This finding in normal male subjects indicated that the serotonin system may serve as a biological basis for spiritual experiences. The authors speculated that the several-fold variability in 5-HT(1A) receptor density may explain why people vary greatly in spiritual zeal.
Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institute and Hospital, SE-171 76 Stockholm, Sweden.
Jacqueline
J
Borg
Bengt
B
Andrée
Henrik
H
Soderstrom
Lars
L
Farde
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000502:physiology*; D002605:Character; D006624:Hippocampus / Q000000981:diagnostic imaging / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D019579:Neocortex / Q000000981:diagnostic imaging / Q000502:physiology; D010551:Personality / Q000145:classification / Q000502:physiology*; D010552:Personality Assessment / Q000706:statistics & numerical data; D010555:Personality Inventory / Q000706:statistics & numerical data; D010879:Piperazines; D011725:Pyridines; D011903:Raphe Nuclei / Q000000981:diagnostic imaging / Q000502:physiology; D011985:Receptors, Serotonin / Q000378:metabolism / Q000502:physiology; D012701:Serotonin / Q000502:physiology*; D012702:Serotonin Antagonists; D029181:Spirituality; D013694:Temperament / Q000502:physiology; D014055:Tomography, Emission-Computed
D010879:Piperazines; D011725:Pyridines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide