Vasopressin Levels in Spinal Fluid Linked to Aggression in People with Personality Disorders | Research

The takeaway

Higher levels of the peptide hormone vasopressin in cerebrospinal fluid were correlated with greater aggression in personality-disordered individuals, independent of serotonin function.

Independent of serotonin
Vasopressin's link to aggression persisted even after accounting for serotonin function, suggesting a separate biological pathway

What the researchers found

Cerebrospinal fluid levels of arginine vasopressin (AVP) were directly correlated with life history of general aggression and aggression against persons in people with personality disorders. Higher vasopressin in the brain was linked to more aggressive behavior.

Importantly, vasopressin levels were inversely correlated with serotonin function (measured by prolactin response to d-fenfluramine), and lower serotonin function was also linked to greater aggression. However, the relationship between vasopressin and aggression remained significant even after accounting for serotonin's influence, suggesting vasopressin has its own independent role in promoting aggressive behavior beyond the well-known serotonin connection.

Why it matters

This study was among the first to demonstrate in humans what animal research had long suggested: that vasopressin, a peptide hormone primarily known for regulating water balance and blood pressure, also plays a role in aggressive behavior in the brain. By showing that vasopressin promotes aggression through a pathway independent of serotonin, it opened up a potential new target for managing pathological aggression in personality disorders.

The numbers in context

n=26 personality-disordered subjects · CSF AVP correlated with general aggression and aggression against persons · Inverse correlation between CSF AVP and PRL[d-FEN] serotonin index · AVP-aggression link persisted after controlling for serotonin variance

How the study worked

Researchers collected cerebrospinal fluid from 26 adults meeting DSM-IV criteria for personality disorder. They measured vasopressin (AVP) and serotonin metabolite (5-HIAA) levels in the spinal fluid. Serotonin function was also assessed using a d-fenfluramine challenge test, which measures prolactin release as a proxy for central serotonin activity. Aggression was quantified using the Life History of Aggression assessment, and impulsivity was measured with the Barratt Impulsiveness Scales. Statistical correlations were then calculated between the biological markers and behavioral measures.

Who was studied

Adults meeting DSM-IV criteria for personality disorder

What this study cannot tell us

The sample size of 26 is very small, limiting statistical power and generalizability. The cross-sectional design cannot establish whether high vasopressin causes aggression or is a consequence of it. Only personality-disordered subjects were included, so findings may not apply to the general population. CSF sampling captures a single time point and may not reflect dynamic fluctuations in neuropeptide levels.

How to read the evidence

This is a small cross-sectional study of 26 subjects, which limits statistical power and cannot establish causation. While it provides important preliminary human evidence for a concept well-supported in animal research, the findings need replication in larger samples before drawing firm conclusions.

When this study was published

Published in 1998 in Archives of General Psychiatry. Despite its age, this remains a frequently cited foundational study linking central vasopressin to human aggression. Subsequent research has largely supported these findings.

The bigger picture

This study contributed to a growing understanding that aggressive behavior is regulated by multiple neuropeptide systems, not just serotonin. The finding that vasopressin has an independent aggression-promoting effect opened a new avenue for understanding violence in psychiatric conditions and raised the possibility that vasopressin receptor antagonists could someday be explored as treatments for pathological aggression.

Questions still open

Could vasopressin receptor antagonists reduce aggressive behavior in people with personality disorders?
Does this vasopressin-aggression relationship exist in people without personality disorders, or is it specific to this population?
How do vasopressin levels fluctuate over time, and does acute stress change the relationship with aggression?

Common questions

What does vasopressin have to do with aggression?

While vasopressin is best known for regulating water balance and blood pressure, it also acts as a signaling molecule in the brain. Animal studies have shown it promotes aggressive and territorial behavior. This study provided some of the first human evidence that the same connection exists — people with higher vasopressin levels in their brain fluid had more aggressive histories.

Does this mean vasopressin causes violence?

Not exactly. This study found a correlation — people with higher vasopressin levels tended to be more aggressive — but it cannot prove vasopressin directly causes the behavior. Aggression is complex and involves many biological, psychological, and social factors. Vasopressin appears to be one piece of a larger puzzle.

Read the original research

Cerebrospinal fluid vasopressin levels: correlates with aggression and serotonin function in personality-disordered subjects.

Archives of general psychiatry, 55(8), 708-14

View on PubMed ↗

Citation

Coccaro, E F; Kavoussi, R J; Hauger, R L; Cooper, T B; Ferris, C F. (1998). Cerebrospinal fluid vasopressin levels: correlates with aggression and serotonin function in personality-disordered subjects.. Archives of general psychiatry, 55(8), 708-14.