Effect of Intranasal Neuropeptide on Emotion Perception in Trait Anxiety

Extensive research has been conducted to examine cognitive styles in anxiety disorders that may contribute to the psychopathology of these disorders. One of the most consistent findings has been that anxious subjects attend preferentially to threatening stimuli. This attentional bias, which would increase time spent attending to and processing threatening stimuli such as words, sentences, or faces, is thought to help provoke and maintain anxiety states. This is supported by research that demonstrates that reduction in anxiety symptoms is associated with a decrease in attentional bias. Related to an attentional bias is the concept of a perceptual bias, from which people with anxiety disorders may be more perceptive to negative emotional cues. For example, Duncan and Barrett (2007) found a negative correlation between objective awareness of quickly presented faces depicting fear and extraversion. Participants who reported greater extraversion (i.e., pleasure derived from social interactions) were less likely to see 16 ms presentations of faces depicting fear. Thus, it appears that how someone feels is related to and may influence the information they see in their environment. The investigators thus hypothesize that the presence of chronic anxiety disorders may be linked to perceptual biases, and may actually influence how and what information they perceive (their sensory experience). People with anxiety disorders may be less likely to see positive objects and more likely to see negative objects. Although the neurobiological mechanisms underlying these anxiety disorders remain uncertain, one hypothesis implicates the dysregulation of the neuropeptide oxytocin.

Oxytocin is a nine-amino-acid peptide which has a role in maintaining social behavior, and it has been found to decrease anxiety. Researchers have postulated that the anti-anxiety affects of oxytocin are related to the trust and pro-approach behaviors associated with this peptide. For example, mice treated with oxytocin spend more time in the previously avoided open areas of a maze. In a study in humans using healthy volunteers, participants were administered oxytocin or placebo before they played a game with monetary rewards involving trust with a stranger. Those who received oxytocin transferred higher amounts of money to the other player than those who received placebo. This behavior, involving increased comfort with a novel individual or setting, appears to be related to the effects of oxytocin.

As described above, individuals with high levels of anxiety have a perception bias towards emotional stimuli, such as pictures of faces. Oxytocin's anxiolytic, pro-approach and trust effects may decrease this bias, and may cause an individual to experience people or things in the environment as less threatening.

Inclusion criteria

• No current Axis I according to Diagnostic & Statistical Manual for Psychiatry-IV excluded diagnoses as determined by MINI or Structured Clinical Interview for Diagnosis psychiatric diagnostic interview completed within the past 6 months
• Age 18 to 65
• Subjects must be able to give informed consent and be willing and able to comply with study procedures.

Exclusion criteria

• Patients with severe unstable medical illness, clinically significant laboratory findings, or serious medical illness for which hospitalization may be likely within the next three months
• Pregnant or lactating women.
• Subjects currently taking hormones, such as estrogen.
• Known hypersensitivity to oxytocin or to any of the excipients of Syntocinon Nasal spray.
• Known hyponatremia or concurrent use of diuretics.
• Subjects with a history of seizure disorder.