Mental health of intellectually gifted individuals: Investigating the nonlinearity of the relationship between intelligence and general mental health

Despite intelligence being generally related to better mental health, individuals with extremely high levels of intelligence (also often referred to as gifted) are frequently viewed to be socially maladjusted, emotionally unstable, and eccentric. Although this view has existed for decades, the scientific data on this subject are highly inconsistent and suffer from several methodological limitations. In this study, to test whether the relationship between general intelligence and general mental health is nonlinear in such a way that at extreme values of intelligence the relationship turns from positive to negative the data from eight waves of the 1970 British Cohort Study (BCS70) were used (N range from 2,870 to 7,984), with intelligence being assessed at age 10, and mental health being assessed with several different measures at ages 16, 26, 30, 34, 42, 46 and 50. Quadratic regression, as well as spline regression, which divides the dataset into intervals, creates a separate regression for each interval and then smooths out the breakpoints, was used for analyses. The results showed that the nonlinear models generally fit the data better than the corresponding linear models. At high values of intelligence, individuals might begin to experience unique issues affecting their mental health, despite their mental health being at potentially the same or higher level than those with average intelligence. Intellectually gifted individuals have a large potential to have a positive impact on the functioning of the whole society. Recognizing and understanding their problems may prove to be of great importance.