Cloninger’s Psychobiological Theory of Personality proposes four temperament dimensions, each underpinned by a different neurotransmitter system. The serotonergic system is purportedly linked to Harm Avoidance (HA). The aim of this study was to explore the relationship between HA and serotonin in migraine without aura (MO). A second aim was to explore the personality profile of MO patients. Sixty-six participants completed an online questionnaire and donated blood samples. Results indicated no significant association between HA and serotonin and a significant relationship between MO and HA. This study indicates that both Cloninger’s Psychobiological Theory of Personality and the Tridimensional Personality Questionnaire used for its assessment have value in South African personality research. In addition, the findings of the study reveal support for personality influences on the processes involved in migraine. This not only produces worthwhile avenues of research but also an alternative perspective for clinical practice. / Psychology / M.A. (Psychology (Research Consultation))