Why some obese people become depressed whilst others do not: exploring links between cognitive reactivity, depression and obesity.

Obesity and depression are two major public health concerns, particularly when they co-occur. To date, mechanisms underlying this association have not been established and it is unclear why some obese people become depressed whilst others do not. However, considering the strong association between depression and cognitive reactivity (CR), the present study explores possible associations between obesity, depression and CR in light of the scarce and conflicting nature of past literature. 254 participants were included for measures of depression, CR and obesity. Multivariate analyses of covariance examined the effects of depression and obesity as well as interaction effects of depression x obesity controlling for age and gender. Directions of effects were analysed by means of regression analyses and group contrasts. Linear analyses revealed (1) a significant effect of obesity on the rumination (RUM) and control/perfectionism subscales of CR, (2) a significant effect of depression on CR and all of its subscales, and (3) a significant interaction effect between obesity x depression on RUM. Results may support the 'Jolly Fat Hypothesis' and the existence of a psychologically protected subgroup of obese patients characterised by a lower ruminative thinking style and fewer depressive symptoms. Thus, incorporating anti-rumination therapy into treatment for obese individuals may be beneficial to prevent the development of comorbid depression.