Temperament and Character Inventory

Temperament and Character Inventory (TCI) is an inventory for personality traits devised by Cloninger et al. It is closely related to and an outgrowth of Tridimensional Personality Questionnaire (TPQ), and it has also been related to Zuckerman's and Eysenck's dimensions of personality.

TCI operates with seven dimensions of personality traits with four  so-called temperaments and further three so-called characters Each of these traits have a varying number of subscales. The dimensions are determined from a 240-items questionnaire.
 * Novelty Seeking (NS)
 * Harm Avoidance (HA)
 * Reward Dependence (RD)
 * Persistence (PS)
 * Self-Directedness (SD)
 * Cooperativeness (CO)
 * Self-Transcendence (ST)

Versions
Originally developed in English TCI has been translated to other languages, e.g., Swedish, Japanese, Dutch, German, Korean, Finnish, Chinese and French. There is also a revised version TCI-R. Whereas the original TCI had statements that the subject should indicate whether true or false the TCI-R has a five point rating for each statement. 189 of the 240 statements are common between the two versions. The revised version has been translated into Spanish, French, Czech, and Italian.

The number of subscales on the different top level traits are different between TCI and TCI-R. The subscales of the TCI-R are:
 * Novelty seeking (NS)
 * Exploratory excitability (NS1)
 * Impulsiveness (NS2)
 * Extravagance (NS3)
 * Disorderliness (NS4)
 * Harm avoidance (HA)
 * Anticipatory worry (HA1)
 * Fear of uncertainty (HA2)
 * Shyness (HA3)
 * Fatigability (HA4)
 * Reward dependence (RD)
 * Sentimentality (RD1)
 * Openness to warm communication (RD2)
 * Attachment (RD3)
 * Dependence (RD4)
 * Persistence (PS)
 * Eagerness of effort (PS1)
 * Work hardened (PS2)
 * Ambitious (PS3)
 * Perfectionist (PS4)
 * Self-directedness (SD)
 * Responsibility (SD1)
 * Purposeful (SD2)
 * Resourcefulness (SD3)
 * Self-acceptance (SD4)
 * Enlightened second nature (SD5)
 * Cooperativeness (C)
 * Social acceptance (C1)
 * Empathy (C2)
 * Helpfulness (C3)
 * Compassion (C4)
 * Pure-hearted conscience (C5)
 * Self-transcendence (ST)
 * Self-forgetful (ST1)
 * Transpersonal identification (ST2)
 * Spiritual acceptance (ST3)

Neurobiological foundation
TCI has been used for investigating the neurobiological foundation for personality together with other research modalities, e.g., with molecular neuroimaging, structural neuroimaging and genetics.

Cloninger suggested that the three original temperaments from TPQ, novel seeking, harm avoidance and reward dependence, was correlated with low basal dopaminergic activity, high serotonergic activity, and low basal noradrenergic activity, respectively.

Many studies have used TCI for examining whether genetic variants in individual genes have an association with personality traits. Studies suggest that novelty seeking is associated with dopaminergic pathways. Dopamine transporter DAT1 and dopamine receptor DRD4 are associated with novelty seeking. Parkinson's patients, who are intrinsically low in dopamine, are found to have low novelty seeking scores. Gene variants that have been investigated are, e.g., 5-HTTLPR in the serotonin transporter gene and gene variants in XBP1.