High IQ No Protection Against Suicidal Thoughts in Youth
Batya Swift Yasgur, MA, LSW
April 11, 2019
Suicidal ideation (SI) occurs more frequently in adolescents with superior cognitive performance than in youngsters with lower cognition, new research suggests.
Investigators studied more than 6000 typically developing community-based adolescents aged 11 to 21 years and compared the cognitive and social functioning of those with and those without SI.
After controlling for depression or general psychopathology, the investigators found that youth with SI showed greater psychopathology and poorer level of function but better overall neurocognitive performance.
Although greater functional impairment was observed in females with SI, the association of superior neurocognition with SI was more prominent in postpubertal males.
"Kids with past suicide ideation had, as expected, more psychopathology across the board," lead author Ran Barzilay, MD, PhD, child and adolescent psychiatrist and research scientist, Lifespan Brain Institute at Children's Hospital of Philadelphia and the University of Pennsylvania, told Medscape Medical News.
However, when comparing the two groups, "we were surprised that the kids with a history of suicidal ideation performed better on neurocognitive testing — although, if we want to granulate the findings, it was more evident post puberty, during late adolescence," Barzilay said.
"I'd like to make clear that this definitely does not mean every smart or gifted child is at risk [for SI] and that parents should panic — only that being smart doesn't protect a child or adolescent from suicidal ideation," he added.
The findings were published online March 28 in the British Journal of Psychiatry.
Suicide is now the second leading cause of death in youth worldwide, and suicidal behavior (defined as ranting from SI, attempt planning, and attempts) is a "major health problem," the authors write.
Although the association of SI with greater psychopathology and poorer functional outcome is "well established in youth," previous literature is "inconclusive regarding how SI in youth is related to cognitive performance, such as obtained from standard neuropsychological testing," the investigators add.
They note that evaluating neurocognitive function in youth who experience SI "may reveal distinct neurocognitive phenotypes that are uniquely associated with SI and may help identify suicide-related risk."
"I am privileged to work on data from the Philadelphia Neurodevelopmental Cohort [PNC]," Barzilay said. The PNC is a large community sample of almost 100,000 community-based children.
"These are not children who are seeking mental health services, so they are 'normally' developing, to use laypersons' language, and have no psychiatric disorders," said Barzilay.
The community sample is racially and socioeconomically diverse, reflects the regional demographics of the Philadelphia area, and is well balanced between males and females.
A "robust profile" of these children is available, based on psychological, psychiatric, and neurocognitive data that include many domains of cognitive function, such as executive function, memory, complex, cognition, and social cognition.
The current analysis, which included participants aged 11 to 21 years, compared those with SI (n = 672) to those without SI (n = 5479).
Participants completed a battery of tests, including a screening interview based on the Kiddie Schedule for Affective Disorder and Schizophrenia, the 1-hour Penn Computerized Neurocognitive Battery (CNB), and the Children's Global Assessment scale (C-GAS), which assessed level of function.
SI was assessed with a single question: "Have you ever thought about killing yourself?"
The 10.9% of the participants who reported SI were older, were of lower socioeconomic status, demonstrated higher rates of lifetime depressive episodes, and had greater overall general psychopathology.
A higher rate of SI was found in postpubertal females compared with males (15.7% vs 12.4%, respectively). This difference was not observed in prepubertal youth (7% to 8% of males and females experienced SI).
The researchers used four domains to assess the association of SI with psychopathology: mood-anxiety, psychosis spectrum, externalizing symptoms, and fear.
In all of these domains, after the investigators controlled for age and socioeconomic status, youngsters with SI showed greater symptomatology, regardless of sex or pubertal status.
Among the psychopathology domains, the augmenting effect of SI on symptom scores was more pronounced for mood-anxiety symptoms compared with the other domains, after controlling for age, sex, and socioeconomic status.
Moreover, those with current thoughts of suicide/death/dying had more severe symptoms in all domains.
Youth with SI demonstrated poorer functioning compared with those without SI (mean C-GAS score, ±SD 68.6 ± 13.7 vs 80.4 ± 11.3, respectively; Cohen's d = .94) after the investigators controlled for lifetime depression or general psychopathology and for demographic covariates. This association was more pronounced in females and during prepubertal adolescence.
In addition, youth with SI who also experienced current thoughts of suicide/death/dying demonstrated lower level of functioning compared with youth who experienced suicidal ideation but who did not currently have such thoughts.
In contrast to the negative association with functioning level, SI was positively associated with better cognitive performance, manifested as overall accuracy on the CNB, after the investigators controlled for lifetime depression, general psychopathology, and demographic covariates. This association remained significant when current suicidal thoughts were included in the regression model.
Postpubertal youth with SI showed marginally higher accuracy in overall cognitive performance compared with their nonsuicidal counterparts. This difference was not observed in prepubertal youth (SI by puberty interaction, P = .046).
This superior cognitive accuracy in postpubertal youth with SI was more prominent in males (Cohen's d = .32) than in females (Cohen's d = 0.11). Inclusion of lifetime depression or general psychopathology in the model resulted in trend level significance (SI by puberty interaction, P = .055 and P = .051, respectively).
To analyze performance in specific neurocognitive domains for both males and females, spanning from before puberty to after puberty, the researchers compared the accuracy of youth with SI with that of the control group in all cognitive tasks.
They found that postpubertal males with SI outperformed their counterparts who did not experience SI in tasks across cognitive domains, including executive function, episodic memory (verbal), complex reasoning, and the social cognition–related age differentiation task (for all, P < .05).
By contrast, postpubertal females with SI outperformed their counterparts without SI only in a task on the Penn Matrix Reasoning Test (P < .05).
In prepubertal youth, there were no significant differences between the sexes with respect to those with and those without SI.
"The findings are a little counterintuitive, because you usually expect people who perform better cognitively to function better; but in this situation, the function [of those with SI] was worse, but their cognition was better," Barzilay said.
He added that the reason for the association is not clear, but speculated that youth who have higher cognitive capacity might contemplate existential questions more deeply than their peers.
Whatever the reason, the take-home message is clear, Barzilay noted.
"Poor function goes with suicidal ideation. Therefore, if a youngster is showing poor function, it should be seen as a red flag, and higher cognition doesn't mean you can remove the red flag," he said.
More Worries, More Pressure?
Commenting on the study for Medscape Medical News, Gregory Plemmons, MD, associate professor of pediatrics, Monroe Carell Jr Children's Hospital, Vanderbilt University Medical Center, Nashville, Tennessee, agreed that neurocognition and intelligence "are not protective against suicidal ideation."
In addition, "suicide and depression appear to affect adolescents of both genders across a spectrum," noted Plemmons, who was not involved in the research.
He suggested several reasons why youth with higher cognition might experience more SI.
"Many of these individuals may be more susceptible to depression or mood disorders, with heightened tendencies to worry or ruminate about things," Plemmons said.
Moreover, "higher IQ individuals may also have more performance anxiety and increased pressure to excel in school, which can increase pressure," he added.
"Being smart is not a risk factor for suicidal ideation; but at the same time, parents should realize that no child is 'too smart' to think about or complete suicide," he said.
The study was supported by the National Institutes of Health, the Dowshen Neuroscience fund, the Lifespan Brain Institute of Children's Hospital of Philadelphia, and Penn Medicine at the University of Pennsylvania. Barzilay reports serving on the scientific board of and owning stock in Taliaz Health, but has no conflicts of interest relevant to this work. The other authors' relevant financial relationships are listed in the original article. Plemmons has disclosed no relevant financial relationships.
Br J Psychiatry. Published online March 28, 2019. Abstract