- To investigate whether Fibromyalgia (FM) patients differ from their first-degree relatives with and without FM regarding the four personality traits, based on Cloninger's TPQ questionnaire (1). The study population was obtained from a genetic study from 2003-2007 and included 129 female FM patients, 27 female relatives with undiagnosed FM and 30 female relatives without FM. All participants completed a socio-demographic questionnaire and the Tridimensional Personality Questionnaire (TPQ) (1) that refers to four personality dimensions: 'novelty seeking', 'harm avoidance', 'reward dependence' and 'persistence'. Non-articular tenderness was evaluated by tender point count and by dolorimetry. FM patients and their relatives with FM had higher scores on 'harm avoidance' than relatives without FM (p<0.001, p=0.017 respectively). Furthermore, the mean point counts of FM patients were significantly higher and their tenderness thresholds were significantly lower than that of their relatives in the other two groups (p<0.001; p<0.001, respectively). The findings suggest that relatives with FM display personality resemblance to FM patients especially in the personality trait harm avoidance. It appears that there are factors in this personality trait that are hereditary and that may contribute to the development of FM. However, the results could not differentiate between factors from a genetic or a non-genetic origin, due to the study design. In addition, FM's place as an independent component among genetic disorders such as pain, depression and anxiety is still unclear.