Narcissism is a complex personality trait that involves grandiosity, self-focus, and a lack of empathy. The cause of narcissism has been widely debated, with some researchers arguing it is more influenced by genetics while others emphasize environmental factors. Here we review the evidence on both sides of this discussion.
What is narcissism?
Narcissism is characterized by an inflated self-image and obsession with receiving admiration and special treatment. People high in narcissism tend to be entitled, exploitative, and envious of others. At the extreme, narcissism can be diagnosed as Narcissistic Personality Disorder (NPD).
According to the DSM-5 diagnostic manual, symptoms of NPD include:
- Grandiosity and feelings of superiority
- Fantasies of success, power, and attractiveness
- The need for constant admiration
- Exploiting interpersonal relationships for personal gain
- Lack of empathy
These characteristics reflect an excessive preoccupation with the self and a lack of interest in others’ needs. NPD affects around 6% of the population to some degree.
Is there a genetic basis for narcissism?
There is some evidence that genetics play a role in narcissism:
- Twin studies show modest heritability – genetics account for around 40% of variance in narcissism scores.
- Polymorphisms in genes related to neurotransmission may be linked to narcissism. For example, a variation of the serotonin transporter gene 5-HTT is associated with higher narcissism.
- Children of parents with NPD are more likely to develop narcissistic traits.
- Personality traits like extraversion and neuroticism that overlap with narcissism have a strong genetic basis.
Overall, while genetics don’t account for everything, they seem to play a meaningful role in increasing vulnerability to narcissism.
Twin studies
Research comparing identical and fraternal twins allows estimation of the heritability of personality traits. Identical twins share 100% of their DNA while fraternal twins share only around 50%. By comparing how similar identical and fraternal twin pairs are on narcissism measures, we can estimate how much variance genetics accounts for.
For example, a 2008 meta-analysis by Vernon, Villani, Vickers, and Harris reviewed 11 twin studies related to narcissism and found an average heritability of 39%. In other words, genetics explained about 39% of individual differences in narcissistic personality.
Molecular genetics
In addition to twin studies, research on specific genetic variants provides further evidence for biological influences on narcissism:
- A 2008 study found that having one or two copies of the short allele of 5-HTT, the serotonin transporter gene, was associated with higher narcissism compared to having two long alleles.
- A 2015 study reported a link between a variant of the oxytocin receptor gene (OXTR) and entitlement and authority facets of narcissism.
- Other candidate genes like DAT1 and DRD2 related to dopamine neurotransmission have been linked to narcissism in preliminary studies.
Though more research is needed, these findings support narcissism having some genetic underpinnings.
Intergenerational transmission
If genetics influence narcissism risk, having a parent with NPD should increase a child’s likelihood of developing narcissistic traits. And indeed, studies show children of parents with NPD are more narcissistic than average.
For example, a 2006 study found that people with an NPD parent reported higher entitlement and exploitativeness. And a 2015 study showed people with narcissistic mothers had more narcissistic and antisocial personality features.
Parental NPD isn’t destiny – environment matters too. But these findings show narcissism can run in families, hinting at heritability.
Evidence for environmental causes
Though genetics play a role, most experts agree environmental factors also impact narcissism development. Support for nurture influencing narcissism comes from several sources:
- Childhood adversity and trauma increase narcissism risk.
- Parenting practices like overvaluation can foster narcissism.
- Social learning contributes to narcissistic attitudes like entitlement.
- Personality traits overlap but are distinct constructs from narcissism.
Overall, life experiences seem to interact with genetic factors to shape narcissistic tendencies.
Childhood adversity
Exposure to stressful and traumatic events in childhood is linked to increased narcissism later in life. For example, studies show abuse, emotional neglect, insecure attachment, and unstable early caregiving can heighten narcissistic tendencies.
A 2018 meta-analysis summarized results from 15 studies exploring associations between adverse childhood events (ACEs) and narcissism. Experiencing ACEs like abuse or household dysfunction before age 18 predicted higher narcissism in adulthood.
Childhood adversity may foster insecure attachment and oversensitivity to threats. This can lead to defensive self-aggrandizement and the inflated, fragile ego characteristic of narcissism.
Parenting factors
How parents interact with children also influences narcissism development. Two key parenting dimensions connected to narcissism are:
- Overvaluation – Excessive praise and positive feedback that communicates children are superior to others.
- Lack of warmth – Emotional coldness and low responsiveness to the child’s needs.
Overvaluing parenting fosters grandiose narcissism while cold, detached parenting is associated with vulnerable narcissism. Both contribute to an insecure, exaggerated sense of self.
Social learning
Narcissistic attitudes like entitlement and dominance orientation can also be learned through modeling and reinforcement. For example, children with narcissistic parents may observe and internalize exploitative behaviors.
Broader cultural values also play a role. Cultures that emphasize individualism, competition, and status encourage narcissistic conduct. Feelings of privilege and superiority are more likely to emerge in these contexts.
Overlap with other traits
Narcissism correlates with traits like extraversion and neuroticism that are clearly influenced by environment as well as genes. This suggests narcissism itself is also shaped by experience, not just DNA.
And while personality traits are heritable, studies show narcissism is linked to life experiences and parenting above and beyond overlapping traits. So while related, narcissism is distinct from core personality dimensions.
Conclusion
In summary, narcissism appears to be influenced by both genetic and environmental factors. Twin studies show modest heritability, meaning DNA differences account for around 40% of variance in narcissistic personality. Specific genes like 5-HTT also seem connected to narcissism risk. Having a narcissistic parent increases a child’s likelihood of developing narcissism as well.
At the same time, childhood adversity, parental overvaluation, social learning, and cultural values contribute to narcissism. Environment and genetics likely interact – adversity may activate biological risk, while parenting can amplify inborn tendencies. This helps explain why narcissism manifests to varying degrees across different contexts.
While more research is needed, the evidence to date suggests narcissism stems from a combination of genetic vulnerability and life experiences. Identifying protective factors that can counteract both biological and environmental risks remains an important goal for improving public mental health.