Is IQ related to different mental health challenges?

Note: This is a section of a longer article. To go to the start, click here.

Not in our sample. To evaluate this question, we asked all our participants both whether they have been diagnosed with different mental health conditions, as well as whether they believe they currently suffer from them. These included: 

• anxiety disorder, 

• major depressive disorder, 

• bipolar disorder, 

• psychosis disorder, 

• personality disorder, 

• food disorder, 

• sleep disorder, 

• sex disorder, 

• impulse disorder, 

• dissociation disorder, 

• development disorder, 

• conduct disorder, 

• attention deficit hyperactivity disorder (ADHD) and 

• autistic spectrum disorder. 

Most of the correlations we obtained were negative, but in terms of magnitude, they were extremely low and practically negligible (between r = 0 and r = -0.1, n = 3688). 

What do the other studies say?

The existing studies that examined the relationship between cognitive ability and mental health have used vastly different approaches and designs and arrived at different conclusions for different mental health issues. Findings in these studies are often contradictory and inconclusive. For example, regarding the relationship between cognitive ability and anxiety or depression, studies so far generally show either negative relationships with IQ or non-existent relationships, but there are exceptions. A meta-analysis by Martin et al. (2010) that compared the mental health of gifted and nongifted youth (which can be seen as a proxy for cognitive ability) found that gifted children exhibited significantly lower levels of anxiety than nongifted children, but found no differences regarding depression or suicidal ideation. Two studies correlated childhood cognitive ability with mental health outcomes in adulthood. A study by Hatch et al. (2007) on n = 1875 participants found that childhood cognitive ability was associated with reporting fewer symptoms of anxiety and depression in women, but not men. Wraw et al. (2016), in a sample of n = 5793 participants,  found that higher childhood cognitive ability predicted decreased self-reported mental health problems in adulthood, but, surprisingly, increased risk of receiving a diagnosis of depression by the age of 50. However, the effect sizes here were quite low. Finally, a big study by Williams et al. (2023) that compared a high g-factor group (g-factor 2 SD above the UK mean; n = 16,137) with an average g-factor group (g-factor within 2 SD of the UK mean; n = 236,273) found that  individuals with high g-factors had less general anxiety but there were no differences regarding the depression. 

On the other hand, some studies found a positive correlation between cognitive ability and other mental health issues. For example, Karpinski et al. (2018) compared Mensa members’ scores of mood and anxiety disorders, attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) with national averages and found that Mensa members scored higher on questionnaires that assessed these disorders in comparison to national averages. On the other hand, Mensa members are self-selecting, and may differ from the general high IQ population. 

The results so far on the relationship between cognitive ability and mental health are complex and inconclusive.

Takeaways

• IQ was not related to any of the 14 mental challenges we screened in our study, and more broadly there is a lack of consensus on the relationship between IQ and mental health.

If you'd like to read the full report, of which this is a section, as one long PDF, you can download it here.

And if you'd like to understand where your intellectual strengths and weaknesses lie, try the cognitive assessment tool that we developed out of this research:

Launch the Cognitive Assessment!