Determining the Relationship between Personality and Depression Using Midus Data

Introduction: Twenty percent of the people in the U.S. experience mental illness. Depression, one of the most dominant forms of mental illness, impacts millions of lives. While interventions have been effective in treating depression, it is challenging to predict the onset of the condition. Personality is generally measured in terms of openness, conscientiousness, extroversion, agreeableness, and neuroticism. Significant changes in neuroticism of individuals who experience mental illness has been observed. The personality measures such as neuroticism and conscientiousness were significantly different for retired individuals who experienced depression after 4 years, as compared to individuals who did not experience depression. However, the effect of other measures of personality on depression and other mental health issues are not clear. In addition, it has not been tested if such a relationship between mental health and personality exists in younger and non-retired population. Therefore, in this paper we study the association between mental issues and personality in a representative sample.

Method: we use survey, data of the three waves of The Midlife in the United States (MIDUS), namely MIDUS 1 (n = 7,108), MIDUS 2 (n=4,963) and MIDUS 3 (n = 3,294). MIDUS is a longitudinal study involving participants above the age of 20 years. We use propensity score matching to develop treatment and control groups. Logistic regression analysis was used to identify the relationship between personality and mental health as well as change in personality and mental health.

Result: There is a significant relationship between personality and depression. Individuals were more likely to report depression in MIDUS 2 if they exhibited lower level of conscientiousness (p=0.07) and extroversion (p<0.05) and higher level of neuroticism (p<0.05) and agreeableness (p=0.06) on MIDUS 1. Similarly, individuals with lower level of conscientiousness and extroversion and higher level of neuroticism on MIDUS 2 were more likely to report depression (p<0.05) in MIDUS 3. Individuals were more likely to report depressive symptoms in MIDUS 3, if they reported lower level of extroversion (p=0.06) and higher level of neuroticism (p<0.05) in MIDUS 1.

Additionally, personality change and depression are related. After 10 years (MIDUS 1, 2 and 3 data were collected at a gap of 10 years), the neuroticism among individuals who experience mental health issue was significantly higher (p<0.05) as compared to individuals who did not experience mental health issue.

Conclusion: Personality and depression are related. Findings of the study will allow us to identify vulnerable population and improving interventions.