European Psychiatry - Volume 33 - March 2016

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24th European Congress of Psychiatry / European Psychiatry 33S (2016) S72–S115 S91
However, other researchers maintain that the effect size of this
deficit is modest and that it lacks clinical significance. The cur-
rent investigation examines a potential alternative explanation for
difficulties in response inhibition, namely enhanced action ten-
dencies in response to stimuli. Therefore, early processes of motor
response preparation preceding action performance (or inhibition)
were studied with the event-related potential (ERP) component
of readiness potential (RP). RP measures brain reactions related to
motor activity in response to external stimuli. ERPs were recorded
while 15 participants with OCD and 16 healthy controls performed
a variation of a go/no-go task and a stop-signal task using schematic
faces (angry and neutral). The OCD group presented with a greater
RP slope gradient and amplitude over bilateral parietal areas cor-
responding to the motor cortex. The amplitude effect was further
enhanced under negative valence, compared with the neutral con-
dition. Differences in RP between the OCD and control groups
remained significant when controlling for levels of trait anxiety.
Results support the hypothesis that a stronger readiness for action
might characterize OCD, especially in the presence of threatening
stimuli. This finding, specific to OCD and not to anxiety symptoms,
may underlie habitual tendencies in OCD. This study suggests that
early-stages of motor preparation might be important to the etiol-
ogy and maintenance of OCD.
Disclosure of interest The authors have not supplied their decla-
ration of competing interest.
Pain and treatment options
FC49
The net suppression effect of pain
catastrophic cognition on anxiety
sensitivity
W. Wong ∗ am Lim ong hen how
R. Fielding
1 Hong Kong Institute of Education, Department of Special Education
& Counseling, Hong Kong, China
2 Hong Kong Institute of Education, Department of Psychological
Studies, Hong Kong, China
3 United Christian Hospital, Department of Anesthesiology, Pain
Medicine & Operating Services, Hong Kong, China
4 Queen Mary Hospital, Department of Anesthesiology & Operating
Services, Hong Kong, China
5 Alice Ho Miu Ling Nethersole Hospital, Department of
Anesthesiology & Operating Services, Hong Kong, China
6 University of Hong Kong, School of Public Health, Hong Kong, China
∗ Corresponding author.
Introduction The existing literature on chronic pain points to
the effects anxiety sensitivity, pain hypervigilance, and pain
catastrophizing on pain-related fear; however, the nature of the
relationships remains unclear. The three dispositional factors may
affect one another in the prediction of pain adjustment out-
comes. The addition of one dispositionmay increase the association
between another disposition and outcomes, a consequence known
as suppressor effects in statistical terms.
Objective This study examined the possible statistical suppressor
effects of anxiety sensitivity, pain hypervigilance and pain catastro-
phizing in predicting pain-related fear and adjustment outcomes
(disability and depression).
Methods Chinese patients with chronic musculoskeletal pain
(n = 401) completed a battery of assessments on pain intensity,
depression, anxiety sensitivity, pain vigilance, pain catastrophiz-
ing, and pain-related fear. Multiple regression analyses assessed
the mediating/moderating role of pain hypervigilance. Structural
equationmodeling (SEM) was used to evaluate suppression effects.
Results Our results evidenced pain hypervigilance mediated the
effects of anxiety sensitivity (Model 1: Sobel z = 4.86) and pain
catastrophizing (Model 3: Sobel z = 5.08) on pain-related fear. Net
suppression effect of pain catastrophizing on anxiety sensitivity
was found in SEM where both anxiety sensitivity and pain catas-
trophizingwere included in the same fullmodel to predict disability
(Model 9: CFI = 0.95) and depression (Model 10: CFI = 0.93) (all
P < 0.001) (see
Conclusions Our findings evidenced that pain hypervigilance
mediated the relationship of two dispositional factors, pain cata-
strophic cognition and anxiety sensitivity, with pain-related fear.
The net suppression effects of pain catastrophizing suggest that
anxiety sensitivity enhanced the effect of pain catastrophic cogni-
tion on pain hypervigilance.
Table 1 Multivariate regression analyses of the relationships
between pain hypervigilance, anxiety sensitivity, pain-related fear.
Table 2 Results of SEM testing the relationships between anxiety
sensitivity, pain catastrophizing, and pain hypervigilance for two
pain adjustment outcomes.