a health hazard and thus are likely to be in better health. this theory provides a theoretical background for evidence found that supports the idea that intelligence is related to mortality through health behaviours such as wearing a seatbelt or quitting smoking. evolutionary novelty theory emphasises the role of behaviour in the link between mortality and intelligence whereas system integrity emphasis the role of genes. thus system integrity predicts that individuals of higher intelligence will be better protected from diseases that are caused primarily by genetics whereas evolutionary adaptive theory suggests that individuals of higher intelligence will be better protected from diseases that are less heritable and are caused by poor life choices. one study which tested this idea looked at the incidence of heritable and non-heritable cancers in individuals of differing levels of intelligence. they found that those of higher intelligence were less likely to have cancer that was not heritable, that was based on lifestyle, thus supporting the evolutionary novelty theory. however this was only a preliminary study and only included the disease cancer, which has been found in previous studies to have an ambiguous relationship with intelligence. disease and injury prevention having higher intelligence scores may mean that individuals are better at preventing disease and injury. their cognitive abilities may equip them with a better propensity for understanding the injury and health risks of certain behaviours and actions. fatal and non-fatal accidental injury have been associated with lower intelligence. this may be because individuals of higher intelligence are more likely to take precautions such as wearing seat belts, helmets etc. as they are aware of the risks. further there is evidence that more intelligent people behave in a healthier way. people with higher iq test scores tend to be less likely to smoke or drink alcohol heavily. they also eat better diets, and they are more physically active. so they have a range of better behaviours that may partly explain their lower mortality risk.— -dr. david batty individuals with higher cognitive abilities are also better equipped for dealing with stress, a factor that has been implemented in many health problems ranging from anxiety to cardiovascular disease. it has been suggested that higher intelligence leads to a better sense of control over one's own life and a reduction in feelings of stress. one study found that individuals with lower intelligence experienced a greater number of functional somatic symptoms, symptoms that cannot be explained by organic pathology and are thought to be stress related. however most of the relationship was mediated by work conditions. disease and injury management there is evidence that higher intelligence is related to better self-care when one has an illness or injury. one study asked participants to take aspirin or a placebo on a daily basis during a study on cardiovascular health. participants with higher intelligence persisted with taking the medication for longer than those with lower intelligence indicating that they could care for themselves better. studies have shown that individuals with lower intelligence have lower health literacy and a study looking at the link between health literacy and actual health found that it was mediated almost entirely by intelligence. it has been claimed that up to a third of medications are not taken correctly and thus jeopardize the patients' health. this is particularly relevant for those with heart problems as the misuse of some heart medications can actually double the risk of death. more intelligent individuals also make use of preventative healthcare more often for example visiting the doctors. some have argued however that this is an artefact of higher ses; that those with lower intelligence tend to be from a lower social class and have less access to medical facilities. however it has been found that even when access to healthcare is equal, those with lower intelligence still make less use of the services. psychiatric illness a diagnosis of any mental illness, even mild psychological distress is linked to an increased risk of illness and premature death. the majority of psychiatric illness' are also linked to lower intelligence. thus it has been proposed that psychiatric morbidity may be another pathway through which intelligence and mortality are related. despite this the direction of causation between intelligence and mental health issues has been disputed. some argue that mental health issues such as depression and schizophrenia may cause a decline in mental functioning and thus scores on intelligence tests, while others believe that lower intelligence increases the likelihood of developing a mental health issue. although evidence for both points of view has been found, most of the cognitive epidemiological studies are carried out using intelligence scores from childhood, when the psychiatric condition was not present, ensuring that it was not the condition which caused the lower scores. this link has been shown to explain part of the relationship between childhood intelligence and mortality, however the amount of variance explained varies from less than 10 percent to about 5 percent. socioeconomic position in adulthood although childhood economic status may be seen as a confounder in the relationship between intelligence and mortality, as it is likely to affect intelligence, it is likely that adult ses mediates the relationship. the idea is that intelligent children will find themselves getting a better education, better jobs and will settle in a safer and healthier environment. they will have better access to health resources, good nutrition and will be less likely to experience the hazards and health risks associated with living in poorer neighbourhoods. several studies have found that there is an association between adult ses and mortality. proposed general fitness factor of both cognitive ability and health, the f-factor because of the above-mentioned findings, some researchers have proposed a general factor of fitness analogous to the g-factor for general mental ability/intelligence. this factor is supposed to combine fertility factors, health factors, and the g-factor. for instance, one study found a small but significant correlation between three measures of sperm quality and intelligence.