Attenuating social anxiety: The effect of oxytocin on (inter-)personal space, mimicry, and communication

Social Anxiety Disorder (SAD) is a common and debilitating mental state, with
prevalence rates between 7 to 13% (Fehm, Beesdo, Jacobi, & Fiedler, 2008). High
socially anxious individuals (HSAs) exhibit excessive fear of being evaluated
negatively. HSAs believe that these evaluations by (significant) others lead to
social rejection or exclusion. Consequently, they avoid social interaction or
endure these with intense stress. SAD has a chronic course, rarely remits
spontaneously, severely disrupts social and occupational functioning, and is
relatively difficult to treat (Heimberg, 2002; Heimberg et al., 1998). So far,
along with distorted cognitions, most recently, deviations in subtle social
behaviors have been identified to play a causal and maintaining role in SAD.
HSA, for example have been shown to keep a larger interpersonal space in an
interaction (Rinck et al., 2010) and show less behavioral mimicry (Vrijsen,
Lange, Becker, & Rinck, 2010). In addition, it is assumed that the non-verbal
communication of HSAs differs from that of healthy controls. These behaviors
are thought to undermine positive evaluation rather than improve it.
Astonishingly, none of these have been investigated with regard to social
affiliation, although, the desire to have good contact with others lies at the
very basis of SAD. In that light, the neuropeptide oxytocin (OXY) has recently
raised considerable interest. OXY is synthesized in the supra-optic (SON) and
the parvoventricular (PVN) nuclei of the hypothalamus and its release is under
serotonergic control (Gimpl & Fahrenholz 2001). Oxytocin has, next to its
peripheral effects (i.e. induction of parturition and lactation), received
attention for its role in social behavior. It reduces social-threat perception
in healthy humans. It ameliorates communication, affiliation, trust but also
the processing of positive social cues (Campbell 2007; Domes, Heinrichs et al.
2009; Kosfeld et al., 2005; Young 2002; Zak, Stanton et al. 2007). In short,
OXY has all effects expected of a successful (psycho-)therapy of SAD without
the considerable side-effects of state-of-the-art psychopharmacological
treatment. Thus, knowledge about its effect on core features of SAD such the
above mentioned behavioral disruptions is of highest importance. Of the only
two studies that have ever explored the effect of OXY on SAD, none has looked
at these specific characteristics. In addition, both have solely included
socially anxious males. This is remarkable as Social anxiety is, after all,
more frequently observed in women.
The proposed studies will be the first to investigate the effects of OXY on
behaviors distinctly related to social interaction, and characteristic for SAD.
The effect of OXY on (a) interpersonal distance (b) mimicry (c) personal space,
and (d) communication will be investigated in females with varying degrees of
social anxiety. The findings will significantly further the understanding of
behavioral distortions in SAD, and of the potential role OXY may play in its
treatment. Results of this study will be used to optimize the design of a
future study to assess the effects of OXY on cognitive biases in individuals
with high and low degrees of social anxiety, and eventually to asses in how far
OXY can serve as adjunct to the treatment of diagnosed SAD patients. These,
however, will be separately communicated to the local ethics committee at that
time.

The main objective of the present protocol is to investigate to what extent
oxytocin modulates specific aspects of interpersonal approach, mimicry, and
communication in healthy volunteers with varying degrees of social anxiety.
Results from this study shall give rise to designing a future study on the
effects of oxytocin on biased cognitions and in patients diagnosed with social
anxiety disorder.

This proposal consists of a double-blind, placebo-controlled, two-way
cross-over experiment. 40 volunteers will be randomly assigned to one of two
treatment sequences. Each volunteer will receive a nasal spray containing
oxytocin or placebo with an interval of about 28 days between each treatment
and subjects will perform a test battery.

per session: 24 intranasal units (IU) of oxytocin, administered twice within
each of the two experimental sessions via a nasal spray containing 2 IU
oxytocin per spray. Two times 12 sprays of oxytocin (6 per nostril) will be
administered. Placebo (PLC) will consist of the vehicle fluid contained in the
oxytocin nasal spray without actual oxytocin. Participants will receive 96 IU
of OXY in total.

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