Obesity is a neurobehavioral illness resulting from a vulnerable brain in a disease-promoting environment. By analogy with mental illness, the search for endophenotypes that are close to mental processes may be fruitful. Endophenotypes are inherited neurobehavioral characteristics that confer vulnerability to illness. Here we will review personality, cognitive, and brain imaging endophenotypes that manifest as neurobehavioral processes that lead to weight gain.
Certain neurocognitive factors appear to predict weight gain. Numerous studies have identified impulsivity, measured either by questionnaires or laboratory tasks, to correlate with body mass index (BMI) and future weight gain. Impulsivity refers to a tendency to act without consideration of consequences. Impulsivity consists of two independent cognitive tendencies: (1) a heightened arousal response to potential rewards and (2) poor self-control. Individuals who score high on Neuroticism (Impulsiveness) and low on Conscientiousness (self-control) are at high risk of developing obesity. These individuals yield to temptation and lack the discipline needed to enact organized behaviors that favour weight control.
We will provide evidence that all the personality traits previously implicated in obesity all map onto a single factor, which we refer to as uncontrolled eating.