Oct 5, 2026·Special Population & Related Conditions
BPD and IQ: What Research Shows About Intelligence in Borderline Personality Disorder
BPD IQ research finds no link to unusually high intelligence: people with borderline personality disorder score modestly lower on several tests on average.
Dr. Russell T. WarneChief Scientist
Share
BPD IQ research does not show that borderline personality disorder comes with unusually high intelligence: in clinical studies, groups with BPD score modestly lower than healthy comparison groups on several cognitive tests, and individual scores span the full ordinary range. The word "borderline" causes a lot of confusion here. In IQ reports, "borderline" usually refers to borderline intellectual functioning, a score range of roughly 70 to 84 that is explained in our guide to low IQ and intellectual disability, and it has nothing to do with borderline personality disorder, a mental health condition marked by unstable emotions and relationships.
This article covers what the meta-analyses find, where the "high IQ BPD" idea comes from, why emotion changes test performance in BPD, and what is known about childhood cognition and change over time. It describes research findings only and is no substitute for an assessment by a psychiatrist or clinical psychologist.
What studies find about IQ in borderline personality disorder
No large study has given full IQ batteries to a representative sample of adults with BPD, so the evidence comes from clinical samples and from tests of specific thinking skills. Two meta-analyses carry most of the weight.
• Ruocco (2005): Pooling 10 studies, Ruocco found that people with BPD performed below healthy comparison groups in all six domains examined, including attention, memory, planning and processing speed. The effect sizes ranged from small for cognitive flexibility (d = -0.29) to large for planning (d = -1.43). A "Cohen's d" expresses a group difference in standard deviation units, so -0.29 is a modest gap and -1.43 is a big one. Ten studies is a small evidence base, and the author noted that the clinical usefulness of the results was limited.
• Unoka and Richman (2016): This later meta-analysis, which also examined co-occurring conditions, found significant deficits in decision making, memory, executive functioning, processing speed, visuospatial ability and verbal intelligence. Patients with more education, and those whose parents had more education, performed better. Samples with more co-occurring depression, eating disorders, substance use disorders or other personality disorders scored worse, while co-occurring anxiety disorders and PTSD made no difference.
Population data point the same way for personality disorders as a group. In a Swedish study of 1,049,663 men tested at conscription around age 18, each standard deviation lower on the IQ test went with a 1.75 times higher risk of later hospital admission for a personality disorder, and men in the lowest IQ band had admission rates 17.8 times those of men in the highest band. That study counted hospital admissions for all personality disorders in men, so it says nothing specific about BPD and nothing about women. Personality disorders are a broad group, and related traits such as narcissism and psychopathy have their own, separate research on intelligence.
The spread within BPD is wide. In one Italian outpatient clinic, 25 of 55 patients with BPD had IQs in the borderline intellectual functioning range (71 to 84) and the other 30 scored between 86 and 124. A Dutch clinical study reported measured IQs from 72 to 124 among its BPD patients. Both are small, selected samples, so they illustrate variability and do not give a population average.
Is there a "high IQ BPD" type?
The idea that people with BPD are unusually intelligent or perceptive circulates widely online, and it has no support in IQ data. It seems to borrow from findings about social perception, which is a different ability.
The best-known example is a Columbia University study that compared 30 people with BPD and 25 healthy controls on the "Reading the Mind in the Eyes" test, where people choose which mental state matches a photograph of someone's eyes. The BPD group scored significantly higher, especially on neutral expressions, and the authors suggested that heightened sensitivity to other people's mental states may feed the social difficulties of the disorder. That is a single small study of one task, and the task measures face reading, a separate skill from reasoning.
Larger syntheses give a more mixed picture of "mentalizing", the capacity to understand behavior in terms of thoughts and feelings:
• Theory of mind tasks: A meta-analysis of 34 studies (1,448 people with BPD and 2,006 controls) found only a modest overall deficit on theory of mind tests (d = 0.36), with no deficit in decoding mental states from faces or eyes. The clearer differences were in reasoning about mental states and in "hypermentalizing", reading more intent into others' behavior than is there.
• Reflective functioning: The same meta-analysis found a very large difference (d = 1.68) on interview-based ratings of reflective functioning, which capture how people make sense of their own and others' minds in real relationships.
None of these measures is an IQ test. Mentalizing overlaps with what is popularly called emotional intelligence, and the distinction between that and reasoning ability is covered in our article on the difference between IQ and emotional intelligence. They are measured in different ways, and a result on one does not stand in for the other.
Emotion-dependent thinking and why testing conditions matter
Psychologists sometimes distinguish "cold" cognition, meaning reasoning on neutral material, from "hot" cognition, meaning thinking while emotions are engaged. In BPD the gap between the two can be large.
In a German brain-imaging study, 22 unmedicated patients with BPD and 22 healthy participants matched for age, education and intelligence did a working memory task while negative or neutral pictures flashed up as distractors. The patients were slower when the distractors were emotional and showed stronger activity in the amygdala, a region involved in emotional reactions. A later study by the same group induced dissociation (feeling detached or numb) in some patients before a similar task, and those patients showed overall working memory impairment. These results suggest that a person's score can depend on their emotional state on the day.
That has practical consequences for interpreting any IQ score in someone with BPD:
• Emotional state: A test taken during a crisis or in a highly distressed state may underestimate typical ability, especially on working memory and processing speed subtests.
• Dissociation: Detached or numb states were linked to overall working memory impairment in the dissociation study described above.
• Co-occurring conditions: Depression, substance use and eating disorders were linked to lower scores in the 2016 meta-analysis, so a low result may partly reflect a second condition.
• Education: Verbal subtests that depend on vocabulary and general knowledge are sensitive to schooling, and the 2016 meta-analysis found that patients with more education performed better.
In the Italian clinic study above, the verbal comprehension index was the score that best separated patients with and without borderline intellectual functioning, and it was closely tied to everyday social functioning. A licensed clinical psychologist or neuropsychologist can give a full battery, compare index scores, and weigh state factors before drawing conclusions.
Childhood cognition and change over time
Long-running cohort studies allow researchers to look at cognition years before any diagnosis. In the E-Risk study of 1,116 families with British same-sex twins, children who showed more borderline-related characteristics at age 12 had, on average, lower IQ scores and less developed theory of mind at age 5, along with more impulsivity and emotional and behavioral problems. These traits at 12 were highly heritable, and harsh treatment in the family before age 10 also predicted them. The IQ difference was one of several early markers, and a group difference like this cannot predict the outcome for any individual child.
The course in adulthood is more hopeful than many people expect. In a 10-year study of 290 people first assessed as psychiatric inpatients, 93% reached a remission of BPD symptoms lasting at least two years and 86% a remission lasting at least four years, although only 50% met the stricter definition of recovery that also required good social and work functioning. Few studies have retested IQ in the same people across that course, so there is little direct evidence on whether scores rise as symptoms remit. Given the role of emotional state in test performance, a score taken during a stable period is likely to be the more representative one.
Frequently asked questions
Do people with BPD have a high IQ?
Research does not support this. Clinical groups with BPD score modestly lower than healthy controls on several cognitive tests on average, and individual IQs range from below average to well above average.
Is "borderline IQ" the same as borderline personality disorder?
No. "Borderline" on an IQ report describes a score range of roughly 70 to 84, while borderline personality disorder is a mental health diagnosis about emotions and relationships. The two are unrelated, though a person can have both.
Does BPD lower IQ?
There is no evidence that BPD causes a lasting drop in general intelligence. Emotional distress and dissociation can lower performance on a given day, as can co-occurring conditions, especially on working memory and speed tasks.
Are people with BPD better at reading emotions?
One small study found people with BPD did better than controls at judging mental states from photographs of eyes, but larger meta-analyses find no consistent advantage and some difficulty in reasoning about other people's intentions.
Can an IQ test diagnose BPD?
No. BPD is diagnosed through a clinical interview by a psychiatrist or clinical psychologist, and an IQ test measures reasoning ability and says nothing about personality.
The takeaway
BPD IQ findings do not match the online idea of a hidden high-IQ type. Across meta-analyses, groups with borderline personality disorder score somewhat below healthy controls on many cognitive tests, with larger gaps when depression or substance use is also present. Performance also drops when emotions run high. Individual scores vary widely, and the word "borderline" on an IQ report refers to a score range and has nothing to do with this diagnosis. If you want to see how a standardized score is built and reported against a defined norm group, you can try a professionally developed IQ test that shows your result with its margin of error.
References
1. Ruocco, A. C. (2005). The neuropsychology of borderline personality disorder: A meta-analysis and review. Psychiatry Research, 137(3), 191-202. [doi.org/10.1016/j.psychres.2005.07.004](. doi.org
2. Unoka, Z., & Richman, M. J. (2016). Neuropsychological deficits in BPD patients and the moderator effects of co-occurring mental disorders: A meta-analysis. Clinical Psychology Review, 44, 1-12. [doi.org/10.1016/j.cpr.2015.11.009](. doi.org
3. Gale, C. R., Batty, G. D., Tynelius, P., Deary, I. J., & Rasmussen, F. (2010). Intelligence in early adulthood and subsequent hospitalization for mental disorders. Epidemiology, 21(1), 70-77. [doi.org/10.1097/EDE.0b013e3181c17da8](. doi.org
4. Galletta, D., Califano, A. I., Micanti, F., Santangelo, G., Santoriello, C., & de Bartolomeis, A. (2020). Cognitive correlates of borderline intellectual functioning in borderline personality disorder. Journal of Psychiatric Research, 130, 372-380. [doi.org/10.1016/j.jpsychires.2020.06.016](. doi.org
5. Muskens, L., Bouwmeester, S., Nooijen, M., & Bachrach, N. (2024). Intelligence and treatment outcome of mentalization-based treatment in borderline personality disorder. Clinical Psychology & Psychotherapy, 31(5), e3061. [doi.org/10.1002/cpp.3061](. doi.org
6. Fertuck, E. A., Jekal, A., Song, I., Wyman, B., Morris, M. C., Wilson, S. T., Brodsky, B. S., & Stanley, B. (2009). Enhanced "Reading the Mind in the Eyes" in borderline personality disorder compared to healthy controls. Psychological Medicine, 39(12), 1979-1988. [doi.org/10.1017/S003329170900600X](. doi.org
7. Bora, E. (2021). A meta-analysis of theory of mind and "mentalization" in borderline personality disorder: A true neuro-social-cognitive or meta-social-cognitive impairment? Psychological Medicine, 51(15), 2541-2551. [doi.org/10.1017/S0033291721003718](. doi.org
8. Krause-Utz, A., Oei, N. Y. L., Niedtfeld, I., Bohus, M., Spinhoven, P., Schmahl, C., & Elzinga, B. M. (2012). Influence of emotional distraction on working memory performance in borderline personality disorder. Psychological Medicine, 42(10), 2181-2192. [doi.org/10.1017/S0033291712000153](. doi.org
9. Krause-Utz, A., Winter, D., Schriner, F., Chiu, C.-D., Lis, S., Spinhoven, P., Bohus, M., Schmahl, C., & Elzinga, B. M. (2018). Reduced amygdala reactivity and impaired working memory during dissociation in borderline personality disorder. European Archives of Psychiatry and Clinical Neuroscience, 268(4), 401-415. [doi.org/10.1007/s00406-017-0806-x](. doi.org
10. Belsky, D. W., Caspi, A., Arseneault, L., Bleidorn, W., Fonagy, P., Goodman, M., Houts, R., & Moffitt, T. E. (2012). Etiological features of borderline personality related characteristics in a birth cohort of 12-year-old children. Development and Psychopathology, 24(1), 251-265. [doi.org/10.1017/S0954579411000812](. doi.org
11. Zanarini, M. C., Frankenburg, F. R., Reich, D. B., & Fitzmaurice, G. (2010). Time to attainment of recovery from borderline personality disorder and stability of recovery: A 10-year prospective follow-up study. American Journal of Psychiatry, 167(6), 663-667. [doi.org/10.1176/appi.ajp.2009.09081130](. doi.org
Hero image: Kintsugi on broken Kyūsu lid-top oblique PNr°1258, by D-Kuru, licensed CC BY-SA 4.0 (creativecommons.org/licenses/by-sa/4.0). Via Wikimedia Commons.
Take our professional IQ test
Want to know your IQ? Try the first ever professional online IQ test.
