[Present contribution of neurosciences to a new clinical reading of obsessive-compulsive disorder].
L'Encéphale. 2007-04-01; 33(2): 203-210
DOI: 10.1016/s0013-7006(07)91551-1
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1. Encephale. 2007 Mar-Apr;33(2):203-10. doi: 10.1016/s0013-7006(07)91551-1.
[Present contribution of neurosciences to a new clinical reading of
obsessive-compulsive disorder].
[Article in French]
Aouizerate B(1), Rotgé JY, Bioulac B, Tignol J.
Author information:
(1)Service de Psychiatrie d’Adultes du Professeur Tignol, Université Victor
Segalen Bordeaux 2, Centre Hospitalier Charles Perrens, Centre Carreire, 121 rue
de la Béchade, 33076 Bordeaux, France.
Obsessive-compulsive disorder (OCD), that affects 2 to 3% of the general
population, is characterized by recurrent intrusive thoughts and repetitive,
time-consuming behaviors. It is a severely incapacitating mental illness that
causes profound impairment in psychosocial functioning and quality of life.
Although the physiopathology of OCD is still far from resolved, the existence of
a biological basis for OCD is now clearly established and should be interpreted
from phenomenological considerations, on the one hand, and in the light of our
increasing knowledge of the physiology of cortico-subcortical functional loops,
on the other. In a phenomenological view, the heart of the obsessional process
is the subject’s underlying impression that « something is wrong ». In other
words, obsessions may be thought of as the permanent perception of a mistake
and/or error in certain behavioral situations. Compulsions occur as behavioral
responses aimed at relieving the tensions or anxiety generated by the situation.
If obtained, this relief may be felt to be a form of reward. Nevertheless, it is
only transient, thereby creating a feeling of considerable anxiety. This
contributes to immediately reproducing the behavior in a cyclic manner, on the
basis of an internal motivational state through an expectation of the reward.
Therefore, it can be assumed that several malfunctioning processes are altered
within the OCD: 1) error recognition; and, 2) emotion and motivation. This
suggests that there is a dysfunction of the brain regions mediating these
cognitive and emotional functions. Experimental neurophysiology in laboratory
animals indicates the central role of the fronto-subcortical circuits
originating in the orbitofrontal and anterior cingulate cortices, respectively.
The orbitofrontal cortex (OFC) and ventromedial areas are involved in appraisal
of the emotional and motivational values of environmental information, and in
integrating the subject’s prior experience, which is crucial in decision-making.
The OFC also contributes to the selection, comparison and judgment of stimuli
and error detection. The anterior cingulate cortex (ACC) is comprised of 1) a
ventral or affective region that could keep attention on the internal emotional
and motivational status and regulation of autonomic responses, and 2) a dorsal
and cognitive region that serves a wide range of functions including attention,
working memory, error detection, conflict monitoring, response selection, and
anticipation of incoming information. Ventral striatum, that is intimately
connected to the OFC and ACC, participates in the preparation, initiation and
execution of behavioral responses oriented toward reward delivery following the
cognitive and emotional integration of behaviorally relevant information at the
cortical level. Functional imaging research in humans has shown an increased
functional activity in the OFC, ACC, head of the caudate nucleus and thalamus in
OCD patients. These functional abnormalities have been found in basal conditions
and during provocation tests. Moreover, the therapeutic efficacy of
antidepressants with preponderant serotonin-reuptake inhibiting properties and
cognitive-behavioral therapies seems to be associated with a progressive
reduction in activity of the OFC, ACC and the caudate nucleus. Therefore, these
observations are suggestive of the responsibility of 5HT neurotransmission in
the dysfunction of the frontal-subcortical loops that emanate from the OFC and
ACC. However, several lines of research suggest that the dopamine system, with
which 5HT interacts, may play a major role in the expression of OC symptoms. In
conclusion, it seems that in OCD there is a dysfunction of the brain regions
that belong to the orbitofrontal and anterior cingulate loops in view of
evidence obtained from separate and complementary approaches.
DOI: 10.1016/s0013-7006(07)91551-1
PMID: 17675916 [Indexed for MEDLINE]