uses substances in amounts or with methods that are harmful to themselves or to others. substance abuse is commonly associated with a range of maladaptive behaviors that are both detrimental to the individual and to society. given the terrible consequences that can transpire from abusing substances, recreational experimentation and/or recurrent use of drugs are traditionally thought to be most prevalent among marginalized strands of society. nevertheless, the very opposite is true; research both in national and individual levels have found that the relationship between iq and substance abuse indicates positive correlations between superior intelligence, higher alcohol consumption and drug consumption. note: illustrative graph only – not based on actual data points, but accurate to trends previously established between alcohol consumption and national iq. for actual data points please refer to belasen and hafer 2013 publication. the relationship between childhood iq scores and illegal drugs use by adolescence and middle age has been found. high iq scores at age 10 are positively associated with intake of cannabis, cocaine (only after 30 years of age), ecstasy, amphetamine and polydrug and also highlight a stronger association between high iq and drug use for women than men. additionally, these findings are independent of socio-economic status or psychological distress during formative years. a high iq at age 11 was predictive of increased alcohol dependency later in life and a one standard deviation increase in iq scores (15-points) was associated with a higher risk of illegal drug use. the counterintuitive nature of the correlation between high iq and substance abuse has sparked a fervent debate in the scientific community with some researchers attributing these findings to iq being an inadequate proxy of intelligence, while others fault employed research methodologies and unrepresentative data. however, with the increased number of studies publishing similar results, overwhelming consensus is that the association between high iq and substance abuse is real, statistically significant and independent of other variables. there are several competing theories trying to make sense of this apparent paradox. doctor james white postulates that people with higher iqs are more critical of information and thus less likely to accept facts at face value. while marketing campaigns against drugs may deter individuals with lower iqs from using drugs with disjoint arguments or overexaggeration of negative consequences, people with a higher iq will seek to verify the validity of such claims in their immediate environment. white also eludes to an often-overlooked problem of people with higher iq, the lack of adequate challenges and intellectual stimulation. white posits that high iq individuals that are not sufficiently engaged in their lives may choose to forgo good judgment for the sake of stimulation. the most prominent theory attempting to explain the positive relationship between iq and substance abuse; however, is the savanna–iq interaction hypothesis by social psychologist satoshi kanazawa. the theory is founded on the assumption that intelligence is a domain-specific adaptation that has evolved as humans moved away from the birthplace of human race, the savanna. therefore, theory follows that as humans explored beyond the savannas, intelligence rather than instinct dictated survival. natural selection privileged those who possessed high iq while simultaneously favoring those with an appetite for evolutionary novel behaviors and experiences. for kanazawa, this drive to seek evolutionary novel activities and sensations translates to being more open and callous about experimenting with and/or abusing substances in modern culture. dementia a decrease in iq has also been shown as an early predictor of late-onset alzheimer's disease and other forms of dementia. in a 2004 study, cervilla and colleagues showed that tests of cognitive ability provide useful predictive information up to a decade before the onset of dementia. however, when diagnosing individuals with a higher level of cognitive ability, a study of those with iqs of 120 or more, patients should not be diagnosed from the standard norm but from an adjusted high-iq norm that measured changes against the individual's higher ability level. in 2000, whalley and colleagues published a paper in the journal neurology, which examined links between childhood mental ability and late-onset dementia. the study showed that mental ability scores were significantly lower in children who eventually developed late-onset dementia when compared with other children tested. health related behaviors alcohol the relationship between alcohol consumption and intelligence is not straightforward. in some cohorts higher intelligence has been linked to a reduced risk of binge drinking. in one scottish study higher intelligence was linked to a lower chance of binge drinking; however, units of alcohol consumed were not measured and alcohol induced hangovers in middle age were used as a proxy for binge drinking. several studies have found the opposite effect with individuals of higher intelligence being more likely to drink more frequently, consume more units and have a higher risk of developing a drinking problem, especially in women. drugs in u.s. study the link between drug intake and intelligence suggests that individuals with lower iq take more drugs. however, in the uk the opposite relationship has been found with higher intelligence being related to greater illegal drug use. smoking the relationship between intelligence and smoking has changed along with public and government attitudes towards smoking. for people born in 1921 there was no correlation between intelligence and having smoked or not smoked; however, there was a relationship between higher intelligence and quitting smoking by adulthood. in another british study, high childhood iq was shown to inversely correlate with the chances of starting smoking. diet one british study found that high childhood iq was shown to correlate with one's chance of becoming a vegetarian in adulthood. those of higher intelligence are also more likely to eat a healthier diet including more fruit and vegetables, fish, poultry and wholemeal bread and to eat less fried food. exercise higher intelligence has been linked to exercising. more intelligent children tend to exercise more as adults and to exercise vigorously. a study of 11,282 individuals in scotland who took intelligence tests at ages 7, 9 and 11 in the 1950s and 1960s, found an "inverse linear association" between childhood intelligence and hospital admissions for injuries in adulthood. the association between childhood iq and the risk of later injury remained even after accounting for factors such as the child's socioeconomic background. socioeconomic status practically all indicators of physical health and mental competence favour people of higher socioeconomic status (ses). social class attainment is important because it can predict health across the lifespan, where people from lower social class have higher morbidity and mortality. ses and health outcomes are general across time, place, disease, and are finely graded up the ses continuum. gottfredson argues that general intelligence (g) is the fundamental cause for health inequality. the argument is that g is the fundamental cause of social class inequality in health, because it meets six criteria that every candidate for the cause must meet: stable distribution over time, is replicable, is a transportable form of influence, has a general effect on health, is measurable, and is falsifiable. stability: any casual agent has to be persistent and stable across time for its pattern of effects to be general over ages and decades. large and stable individual differences in g are developed by adolescence and the dispersion of g in population's intelligence present in every generation, no matter what social circumstances are present. therefore, equalizing socioeconomic environments does very little to reduce the dispersion in iq. the dispersion of iq in a society in general is more stable, than its dispersion of socioeconomic status. replicability: siblings who vary in iq also vary in socioeconomic success which can be comparable with strangers of comparable iq. also, g theory predicts that if genetic g is the principal mechanism carrying socioeconomic inequality between generations, then the maximum correlation between the parent and child ses will be near to their genetic correlation for iq (.50). transportability: the performance and functional literacy studies both illustrated how g is transportable across life situations and it represents a set of largely generalizable reasoning and problem-solving skills. g appear to be linearly linked to performance in school, jobs and achievements. generality: studies show that iq measured at the age of 11 predicted longevity, premature death, lung and stomach cancers, dementia, loss of functional independence, more than 60 years later. research has shown that higher iq at age 11 is significantly related to higher social class in midlife. therefore, it is safe to assume that higher ses, as well as higher iq, generally predicts better health. measurability: g factor can be extracted from any broad set of mental tests and has provided a common, reliable source for measuring general intelligence in any population. falsifiability: theoretically, if g theory would conceive health self-care as a job, as a set of instrumental tasks performed by the individuals, it could predict g to influence the health performance in the same way as it predicts performance in education and job. chronic illnesses are the major illnesses in developed countries today, and their major risk factors are health habits and lifestyle. the higher social strata knows the most and the lower social strata knows the least, whether class is assessed by education, occupation or income and even when the information seems to be most useful for the poorest. higher g promotes more learning, and it increases exposure to learning opportunities. so, the problem is not in the lack of access to health-care, but the patient's failure to use it effectively when delivered. low literacy has been associated with low use of preventive care, poor comprehension of one's illness – even when care is free. health self-management is important because literacy provides the ability to acquire new information and complete complex tasks and that limited problem solving abilities make low-literacy patients less likely to change their behaviour on the basis of new information. chronic lack of good judgement and effective reasoning leads to chronically poor self-management. explanations of the correlation between intelligence and health there have been many reasons posited for the links between health and intelligence. although some have argued that the direction is one in which health has an influence on intelligence, most have focused on the influence of intelligence on health. although health may definitely affect intelligence, most of the cognitive epidemiological studies have looked at intelligence in childhood when ill health is far less frequent and a more unlikely cause of poor intelligence. thus most explanations have focused on the effects intelligence has on health through its influence on mediating causes. various explanations for these findings have been proposed: "first, ...intelligence is associated with more education, and thereafter with more professional occupations that might place the person in healthier environments. ...second, people with higher intelligence might engage in more healthy behaviours. ...third, mental test scores from early life might act as a record of insults to the brain that have occurred before that date. ...fourth, mental test scores obtained in youth might be an indicator of a well-put-together system. it is hypothesized that a well-wired body is more able to respond effectively to environmental insults..." system integrity hypothesis vs evolution hypothesis the system integrity hypothesis posits that childhood intelligence is just one aspect of a well wired and well-functioning body and suggests that there is a latent trait that encompasses intelligence, health and many other factors. this trait indexes how well the body is functioning and how well the body can respond to change and return to a normal balance again (allostatic load). according to the system integrity hypothesis lower iq does not cause mortality but instead poor system integrity causes lower intelligence and poorer health as well as a range of other traits which can be thought of as markers of system integrity. professor ian deary has proposed that fluctuating asymmetry, speed of information processing, physical co-ordination, physical strength, metabolic syndrome and genetic correlation may be further potential markers of system integrity which by definition should explain a large part of or nullify the relationship between intelligence and mortality. an opposing theory to the system integrity theory is the evolutionary novelty theory which suggests that those with higher intelligence are better equipped to deal with evolutionary novel events. it is proposed that intelligence evolved to tackle evolutionarily novel situations and that those with a higher iq are better able to process when such a novel situation is dangerous or