intelligence and mental health

Question 1

mental disorder links to intelligence

Answer 1

• Cognitive epidemiology: The study of the links between intellectual abilities and health & disease
• Intelligence as risk/protective factor: (Longitudinal studies)
• – intelligence in early adulthood predicts hospitalisation for (all) mental disorders and with illness severity (Gale et al., 2010)
• – high childhood intelligence lowers risk of subsequent development of schizophrenia (e.g., Dickson et al., 2012), depression (e.g., Johnson et al., 2011), and Alzheimer’s disease (Anderson et al., 2020)
• Cause or effect? Does low intelligence cause disorder or does disorder cause low intelligence?

Question 2

high intelligence as a risk factor

Answer 2

• Karpinski et al. (2018) show a heightened prevalence of mental disorders in high-IQ individuals
• Sample: members of American Mensa Ltd, a “high IQ society” in the US (N = 3715), who scored in the top 2% on an IQ test
• Hyper Brain/Hyper Body framework

Question 3

contrasting evidence with intelligence and mental illness

Answer 3

• • Caution 1: the findings of Karpinski et al. (2018) are correlational – E.g., people preoccupied with intellectual pursuits may spend less time than the average person on physical exercise and social interaction, both of which have been shown to have broad benefits for psychological/physical health.
• Caution 2: sampling bias (who takes an IQ test and wants to join Mensa?)
• Williams et al. (2022): data from the UK Biobank
• – Compared high (+2 SD above the mean; N=16,137) vs. average IQ group (within +/- 2SD around the mean; N=236,273)
• -High IQ individuals were less likely to have general anxiety and PTSD, were less neurotic, and were no more likely to have any other mental disorders

Question 4

what is the hyper brain hyper body theory

Answer 4

Karpinski and her colleagues developed a hyper brain/ hyper body theory of integration. It posits that individuals with high cognitive ability react with an overexcitable emotional and behavioral response to their environment. Due in part to this increased awareness of their surroundings, people with a high IQ then tend to experience an overexcitable, hyperreactive central nervous system. “In a subset of the high IQ population, a minor trigger such as a clothing tag or an unnatural sound may cause a low level, chronic stress response which then activates a hyper body response. When the sympathetic nervous system becomes chronically activated, it finds itself in a continuous fight, flight, or freeze state that triggers a series of immune changes in both the body and the brain altering behavior, mood, and functioning,” explains Dr. Nicole Tetreault, co-author.