<p><a href="https://doi.org/10.1016/S0191-8869(00)00232-4" rel="nofollow noreferrer">Studies show</a> that the overestimation of one's intelligence is both gender and culture/country dependent.</p>

<p>I don't know of any studies which tried to relate the over/under-estimation of one's intelligence (in measurable terms, rather than generic statements like "I'm stupid") to depression.</p>

<p>There is one <a href="http://www.mdpi.com/2079-3200/6/1/1/pdf" rel="nofollow noreferrer">recent (2017) study</a> in older adults that found a self-reported measure of cognitive abilities to be a stronger predictor of (Big Five) personality than of actual cognitive abilities. Fairly predictably, the correlations were with  Extraversion (positively), Openness to Experience (positively) and Neuroticism (negatively). Although not reporting it in its abstract, a slightly <a href="https://doi.org/10.1016/j.paid.2011.12.040" rel="nofollow noreferrer">older (2012) study, Jacobs et al.</a> also found a (negative) correlation between neuroticism and self-reported fluid IQ (but not for two other kinds: visual and comprehension-knowledge).</p>

<p><a href="https://i.sstatic.net/z80hZ.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/z80hZ.png" alt="enter image description here"></a></p>

<p>As it's fairly well known, <a href="https://doi.org/10.1177%2F2167702615618162" rel="nofollow noreferrer">neuroticism predicts depression (and anxiety)</a>.</p>

<p>Personality traits also correlate with each other though, and the estimate of one's IQ also correlates with the measured IQ. So, Jacobs et al. also regressed the relationship between self-estimated and measured IQ on the personality traits that looked promising. And alas in this model, Neuroticism failed to predict anything in addition what extraversion and agreeableness did (that probably explains why Neuroticism is not mentioned in their abstract.)</p>

<p><a href="https://i.sstatic.net/Pcidg.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Pcidg.png" alt="enter image description here"></a></p>

<p>In their discussion section, Jacobs et al. chalk this off to their sample having a fairly restricted range of IQ.</p>

CC BY-SA 4.0
2018-09-26T13:34:39.987Z
But neuroticism strongly predicts depression. Therefore, if rating yourself as having low intelligence predicts higher neuroticism, then the study you cite good evidence in favor of depressive individuals having lower self-rated intelligence.
Eff
CC BY-SA 4.0
2018-09-26T19:21:10.323Z
@Eff: yes, I'm aware of that, that's why I mentioned this study, even though it's one step removed from what the question is asking for in both directions (the self-reported cognitive measure used there isn't IQ either).
got trolled too much this week
CC BY-SA 4.0
2018-09-26T04:01:41.137Z
2018-09-26T20:00:15.940Z
2018-09-26T20:00:15.940Z
got trolled too much this week
<p>A psychology professor of mine said that anyone who believes themselves to be of only average intelligence is likely suffering from depression or another mental illness that impacts their self-esteem. Is there any source that would corroborate this claim?</p>

CC BY-SA 4.0
2018-09-26T04:37:51.510Z
Why not ask the professor and let us know where that idea came from. Also I wonder because "another mental illness" is far too vague to be of use.
user3169
CC BY-SA 4.0
2018-09-26T15:51:40.117Z
This sounds to me like it might be a joke based on work showing that people on average overestimate their intelligence. If so, I'd be careful to avoid taking jokes too literally.
Bryan Krause
<reference-request><confidence>
Are people who believe they are of average intelligence mentally ill?
Zenon
# Are people who believe they are of average intelligence mentally ill?

(Asked by: username_0 on 2018-09-26)

A psychology professor of mine said that anyone who believes themselves to be of only average intelligence is likely suffering from depression or another mental illness that impacts their self-esteem. Is there any source that would corroborate this claim?

**Tags:** reference-request, confidence

> **Comments:**
> **username_1**: Why not ask the professor and let us know where that idea came from. Also I wonder because "another mental illness" is far too vague to be of use.  
> **username_2**: This sounds to me like it might be a joke based on work showing that people on average overestimate their intelligence. If so, I'd be careful to avoid taking jokes too literally.  

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## 1 answers

### Answer by username_3 on 2018-09-26. Score: 4 | Accepted answer

[Studies show](https://doi.org/10.1016/S0191-8869(00)00232-4) that the overestimation of one's intelligence is both gender and culture/country dependent.

I don't know of any studies which tried to relate the over/under-estimation of one's intelligence (in measurable terms, rather than generic statements like "I'm stupid") to depression.

There is one [recent (2017) study](http://www.mdpi.com/2079-3200/6/1/1/pdf) in older adults that found a self-reported measure of cognitive abilities to be a stronger predictor of (Big Five) personality than of actual cognitive abilities. Fairly predictably, the correlations were with Extraversion (positively), Openness to Experience (positively) and Neuroticism (negatively). Although not reporting it in its abstract, a slightly [older (2012) study, Jacobs et al.](https://doi.org/10.1016/j.paid.2011.12.040) also found a (negative) correlation between neuroticism and self-reported fluid IQ (but not for two other kinds: visual and comprehension-knowledge).

[![enter image description here](https://i.sstatic.net/z80hZ.png)](https://i.sstatic.net/z80hZ.png)

As it's fairly well known, [neuroticism predicts depression (and anxiety)](https://doi.org/10.1177%2F2167702615618162).

Personality traits also correlate with each other though, and the estimate of one's IQ also correlates with the measured IQ. So, Jacobs et al. also regressed the relationship between self-estimated and measured IQ on the personality traits that looked promising. And alas in this model, Neuroticism failed to predict anything in addition what extraversion and agreeableness did (that probably explains why Neuroticism is not mentioned in their abstract.)

[![enter image description here](https://i.sstatic.net/Pcidg.png)](https://i.sstatic.net/Pcidg.png)

In their discussion section, Jacobs et al. chalk this off to their sample having a fairly restricted range of IQ.

> **Comments:**
> **username_4**: But neuroticism strongly predicts depression. Therefore, if rating yourself as having low intelligence predicts higher neuroticism, then the study you cite good evidence in favor of depressive individuals having lower self-rated intelligence.  
> **username_3**: @username_4: yes, I'm aware of that, that's why I mentioned this study, even though it's one step removed from what the question is asking for in both directions (the self-reported cognitive measure used there isn't IQ either).  

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