Most of the research on the comorbidity between affective and personality disorders show a higher percentage of personality disorders in patients with mood disorders than expected in the general population, although the range reported is so extensive. Avoidant, dependence, and borderline personality disorders are the most frequent personality disorders reported in mood disorders. Some studies also have found passive-agressive, narcisistic, histrionic, and paranoid personality disorders are frequent comorbidity personality disorders in patients with mood disorders. Personality disorder is present with an increasing probability when the patient suffers a chronic mood disorder, or when two affective disorders are present in the individual. Moreover, the comorbidity between affective and personality disorders is a poor response predictor of the depressive symptoms when the patient receives pharmacological treatment. The probability of depressive recurrences is higher in patients with affective and personality disorders than in patients with affective disorders but without personality disorders. Dimensional temperament and character view of Cloninger theory became a good manner for evaluating the comorbidity phenomenon. Harm avoidance increase is a good predictor of suffering an affective disorder. In the same direction of categorical view, there are some temperament characteristics that predict a poor longitudinal evolution in mood disorders in patients with pharmacological treatment. The most important are reward dependence decrease and novelty seeking increase. Moreover, novelty seeking increase is a good predictor in depressive patients treated with serotonin recapture inhibitors. Hypothetical hereditary biochemical common basis of temperament and character and depressive disorders is supported by this finding. Polemic and understanding discoveries about personality and affective disorders comorbidity are discused in the present work. Difficulty in researching this comorbidity phenomenon is considerable when we consider the limitations of affective and personality inventories. Also the different views of personality disorders may explain the variability in results obtained in scientific literature. Another factor discussed is the information reference and the importance of the moment when the inventory is applied. Also, we consider the posiblity that personality and affective disorders are simuntaneously present because both belong to common origin. It is important to think over that the increasing comorbidity is influenced by a subgroup of patients with simultaneously presentation, with presentation,increasing consequences if we consider all depressed patients. If we want to recognize different groups of affective disorders, with or without personality disorders, environmental stress must be considered for understanding the begining and longitudinal evolution of affective disorders. At the moment, we do not have epidemiological information about comorbidity between personality and affective disorders if we consider personality disorders the principal sample. Further research as about comorbidity between affective and personality disorders consider some of these important variables for increasing comprehension of the psychiatric syndromes presentation.
