The Relationship Between Intelligence and Depression

If you are intelligent, are you more likely to be depressed? Is it less likely? Do intelligence and depression have any relation?

Are the stereotypes true about melancholy, dark geniuses susceptible to mood swings and bouts with true depression? The research in the area of intelligence and depression shows some conflicting answers.

Lower IQ – More Likely To Be Depressed

One study from the Adult Psychiatric Morbidity Survey in England looking at depression and intelligence concluded that people with a lower intelligence quotient (IQ) are less happy and more likely to develop depressive symptoms than those with higher intelligence.

Test subjects with lower intelligence (an IQ in the 70-79 range, which is considered in the lower spectrum of general intelligence) defined themselves as being less happy than peers with IQs in the upper end of the spectrum (around 120) who were considered "gifted" or above average intelligence. In addition, the survey asked respondents whether they were usually in a good mood, how satisfied with the life they felt, and other questions meant to determine their overall happiness and contentment.

One possibility here is that people with lower IQs, due to less ability and therefore limited life choices (less education, lower earning potential, jobs without insurance, sick days, or vacation, etc.), may end up with an overall lower socioeconomic status, which can bring about a lower quality of life and well-being. 

Another long-term study focused on childhood intelligence and the relationship between low childhood IQs and mental disorders later in life. Researchers at Harvard School of Public Health (HSPH) discovered that children with lower IQs illustrated an increased risk of developing psychiatric disorders (such as mood disorders and anxiety disorders) and having worse mental health outcomes as adults. According to Karestan Koenen, assistant professor of society, human development, and health at HSPH, "Lower childhood IQ predicted an increased risk of schizophrenia, depression, and generalized anxiety disorder. Individuals with lower childhood IQs also had more persistent depression and anxiety and were more likely to be diagnosed with two or more disorders in adulthood."

The participants were part of the Dunedin Multidisciplinary Health and Development Study. The group was comprised of 1,037 children born in Dunedin, New Zealand, from 1972-73. They were initially assessed at age three and evaluated every two years until age 15, then at 18, 21, 26, and 32. Their IQs were tested at ages 7, 9, and 11. Mental disorders were then assessed from ages 18 until 32 by clinicians with no prior knowledge of the participants' history.

Koenen says that these findings might be helpful when treating individuals with mental health disorders. For example, some patients may have more difficulty than others when it comes to following treatment plans or remaining consistent with instructions. These are things that clinicians should take into account during treatment.

These findings may also help in prevention planning. For example, IQ testing may help with early prevention and diagnosis. 

The reason lower childhood IQs might lead to increased risk for mental disorders such as major depression is not yet explained, but there are a few possible theories and factors. One theory suggests that a lower childhood IQ might show a difference in brain health, making an individual more susceptible to certain mental disorders. Another theory is that stress is a culprit. Perhaps children with lower IQs are less equipped to deal with stressful life events or more likely to find themselves in stressful situations. Lesser cognitive ability might make them more vulnerable to developing one or more mental disorders or depressive symptoms.

Depression - More Likely To Perform Poorly On IQ Tests

Another school of thought is that depression and intelligence are related, but depression causes a low IQ "to show up," so to speak. In other words, mental illnesses like depression can lower a person's ability to perform.

An experiment was conducted on two groups: those with varying degrees of depression and those with a healthy mental state. The group with a clinical diagnosis of depression performed significantly poorer on given IQ tests than the group classified as mentally healthy.

Some researchers explained this finding as depression lowering the brain's ability to function appropriately in the area of the frontal cortex (also referred to as the frontal lobe). The frontal cortex is our main control center, responsible for cognitive functions such as reasoning and problem-solving, and it controls judgment, language, memory, and other essential processes. It is the part of the brain that makes us feeling, thinking, acting individuals.

So, if depression is present, any individual, regardless of their IQ, low or high intelligence, cannot make the most of their ability and potential when performing certain activities. 

Higher IQ - Might Mean Depression…And More

So, does this mean that people with a higher IQ do not become depressed? Is high intelligence somehow related to emotional intelligence? Not quite. A brilliant person can also develop depression, just like anybody else.

Other researchers believe that people with above-average IQs may even be more likely to develop mental disorders like clinical depression, bipolar disorder, or anxiety disorders.

In one study published in the British Journal of Psychiatry, strong school performance was linked to nearly four times the average risk of developing bipolar disorder. In addition, research indicated that bipolar disorder might be up to four times more common in straight-A students.

Dr. James MacCabe, the lead researcher at the Institute of Psychiatry, King's College London, says, "We found that achieving an ‘A’ grade is associated with increased risk for bipolar disorder, particularly in humanities and to a lesser extent in science subjects.”

In another study, disorders including depression and bipolar (mood disorders), anxiety disorders, attention-deficit hyperactivity disorder, and autism were assessed. They found that people with a high IQ had a higher risk of developing psychological disorders.

Karpinski and colleagues call this association the hyper brain/hyper body theory. This theory suggests that high intelligence is thought to be associated with psychological and physiological "overexcitabilities," or OEs. An OE is an unusually intense reaction to environmental stimuli.

This can present as a high potential to worry and overthink about what they say or what might occur around them or to them. These tendencies may trigger depression, anxiety, or other responses. However, Karpinski is careful to point out that while this shows a relation, it does not prove that a higher IQ is the cause of having a disorder.

When considering children with higher IQs, depression seems to become more likely the higher the IQ reaches. In "Watching Prodigies for the Dark Side," published in Scientific American, psychiatrist Marie-Noëlle Ganry-Tardy says that around 3% of children are highly gifted (having IQ scores of at least 130), which usually gives them an advantage in school.

However, the advantages begin to dwindle for the most exceptionally gifted (having IQ scores above 140). Ganry-Tardy explains that these unusually bright children become very insightful at a young age. This insightfulness can bring about adult problems, such as being aware of the potential risk of failure or fear of not being accepted by other children. This emotional awareness can immobilize children "to the point of emotional paralysis," says Ganry-Tardy. It is easy to see how these situations could lead to depression, anxiety, and other issues for a child.

Takeaway

It may seem confusing as to which theory, if any, seems the most plausible. For example, does a person who is… 1) not very intelligent have problems leading to depression? 2) depressed have a problem performing intelligently? 3) highly intelligent have tendencies to be depressed? Each theory seems to have support based on the evidence presented in this article.

However, one thing is for certain, regardless of the root causes of depression, it can be a debilitating condition for anyone to experience, no matter what their intelligence level. Therefore, if you or someone you love is experiencing symptoms of depression, please seek help from a mental health professional like the ones at BetterHelp.

Various clinical studies have demonstrated that online therapy is effective in treating depression. Many people who engage in online therapy see a significant reduction in their depression symptoms. Online therapy is also incredibly convenient and often much more cost-effective than traditional in-person therapy models. Depression can be very dangerous, so don’t hesitate to contact a certified mental health practitioner if you notice symptoms.