People with lower IQs tend to be less happy and have poorer health in general than individuals with higher IQs, researchers from University College London reported in Psychological Medicine.

The authors explained that “background happiness” and IQ (intelligent quotient) are independently associated with positive health outcomes. However, previous studies had not been consistent regarding the relationship between IQ and levels of happiness.

The same university carried out a study in 2011 which found that people with higher levels of happiness tended to have longer lifespans, regardless of their overall health status or income.

Dr Angela Hassiotis and team set out to determine what the link between IQ and happiness was and whether social and clinical factors could me compounding factors, and if so, to what extent.

The researchers gathered and studied data from the Adult Psychiatric Survey, England, 2007. All the participants were aged at least 16 years and lived in private households. They included information on 6,870 of them. Happiness was rated according to a validated question on a three-point scale, while verbal IQ was gauged according to the National Adult Reading test. The team analyzed both categorical and continuous IQs.

The authors found that there was a significant link between IQ and levels of happiness:

People with the lowest IQs (IQ of 70 to 99) were found to have the poorest levels of happiness

People with the highest IQ (IQ of 120 to 129) were found to have the highest levels of happiness

Some factors, such as income levels, health, neurotic symptoms and activities of daily living had an impact on people’s levels of happiness. They were found to reduce the link between happiness and IQ by about half

The team concluded:

“Those with lower IQ are less happy than those with higher IQ. Interventions that target modifiable variables such as income (e.g. through enhancing education and employment opportunities) and neurotic symptoms (e.g. through better detection of mental health problems) may improve levels of happiness in the lower IQ groups.”

People in the lower IQ range are more likely to have lower-than-average incomes, the researchers explained. There is also a higher incidence of common mental disorders and suicidal behaviors among individuals with lower IQs.

Dr. Hassiotis said “We found that IQ is associated with self-reported happiness, as levels of happiness were lowest in the lower IQ groups and highest in the higher IQ groups. This is particularly relevant when considering the current political debates on happiness. When looking at the data we saw that people with a lower IQ were less likely to be happier because of higher levels of socio-economic disadvantage such as lower income. They are also less likely to be happy because they need more help with skills of daily living, have poorer health and report more symptoms of psychological distress.”

Co-author, Dr. Afia Ali said that interventions that help reduce social inequalities might improve the levels of happiness among those with lower-than-average IQs. These may include promoting programs that improve public education, reduce unemployment, and targeted health promotion in general practice (primary care). Pro-actively detecting and treating mental health problems earlier on would also contribute towards eventual higher levels of happiness.

Dr. Ali said:

“There is also some evidence that long term intensive strategies directed at young children from socially deprived backgrounds can have a positive impact not only on IQ but also on wellbeing and life opportunities. Such interventions are likely to be costly but the initial costs may be offset by future benefits such as a reduced reliance on state benefits and better mental and physical health.”

Written by Christian Nordqvist