Depression is a universal phenomenon, although its frequency can vary among countries. In Chile, a study showed that 21.67% of the participants stated that they had been diagnosed with this disorder at least once in their lives and that 17.2% of the population had experienced depressive symptoms during the previous year (MINSAL, 2011).

The objective of the Millennium Institute for Depression and Personality Research (MIDAP) is to generate scientific knowledge based on a multidimensional view of depression in interaction with personality, in order to maximize the effectiveness of interventions by identifying the agents and mechanisms of change involved in prevention, psychotherapy, and rehabilitation.

Research objectives of MIDAP:

a.- To provide scientific knowledge about depression and personality based on a multidimensional perspective that integrates cultural, social, developmental, psychological, psycho-physiological, and genetic aspects.

b.- To examine specific age-related characteristics associated with depression and personality during pregnancy/nursing, infancy, adolescence, adulthood, and older adulthood.

c.- To generate knowledge that can nurture mental health policies for the development of improved prevention, therapy, and rehabilitation services.

A multidimensional approach to the study of depression

In order to gain a deep understanding of the causes of depression, treatment effectiveness, and prevention, MIDAP employs a multidimensional approach that taps into the skills of its researchers, who belong to various disciplines, in order to generate an empirical model of the etiology, prevention, intervention, and rehabilitation of depression. This model addresses the relationship between depression and personality, along with the multiple dimensions of human functioning which have been empirically linked to this disease.

Depression and personality

The relationship between personality and depression has been conceptualized in four ways: personality as vulnerability for the development of depression, personality changes as a result of mood alterations, affective temperaments as a manifestation of subclinical depression, and personality traits as influences on the clinical manifestation of depression.

The multiple dimensions of depression

The multiple aspects of the image above have been linked empirically, although separately, to depression. Some studies on culture and depression have shown differences in the epidemiology of the latter in several countries, along with differences in the symptomatic expression of the disease. The importance of the social context for understanding the greater prevalence of depression in certain socioeconomic levels, and in women more than in men, has become evident by means of explanations that link the disease to stressors associated with poverty. From an evolutionary perspective, empirical evidence has stressed the importance of early childhood conditions, the relevance of depression and suicidality in adolescents, and the epidemiological impact of depression on older adults. Cognitive and emotional biases have also received major empirical support, including irrational thinking, memory and attention biases, low self-esteem, attributional styles, and negative thoughts. In psychophysiological research, a salient aspect of the development of the disease is the abnormal response of the hypothalamic-pituitary-adrenal axis, an essential part of the neuro-endocrine system that controls stress response. On the other hand, genetic studies have not managed to identify a single main effect, and have instead addressed various types of connections between the genome and the environment, such as the interaction between the polymorphism of the serotonin transporter gene and adverse life events.