Obsessive-compulsive disorder and thinking illusions
Davide Dèttore
A growing amount of evidence suggests that obsessive-compulsive disorder (OCD) could be associated
with cognitive deficits. OCD patients show mnestic and executive dysfunctions and it is a common
opinion that cognitive dysfunctions can play a relevant role in mnestic alterations of OCD patients by
means of the mediation of ineffective organization strategies.
Other authors evidenced different cognitive alterations in OC subjects, such as inferential confusion
(O’Connor, 2002; Aardema et al., 2005) or cognitive flexibility deficits in problem-solving (Chamberlain
et al., 2006; 2007).
Other researches in inductive and deductive reasoning (Pélissier and O’Connor, 2002; Simpson, Cove,
Fineberg, Msetfi and Ball, 2007; Pélissier, O’Connor and Dupuis, 2009) showed that OC patients need
more information and postpone the final decision.
In the present contribution we wish to underline the existence of some cognitive illusions that are
normal and generalized within the population. Such illusions are able to facilitate the origin and the
maintenance of OCD. We consequently will analyze, following the classification of Pohl (2004), illusions
of thinking (conjunction fallacy, confirmation bias, illusory correlation, illusion of control, biases in
deductive and causal reasoning), illusions of judgement (availability and representativeness, anchoring
effect, validity effect), and memory illusions (associative memory illusions, effects of labelling and
misinformation effect) and their relationships with OCD. In conclusion, we will draw some theoretical
and clinical implications.
Keywords
Obsessive-compulsive disorder, reasoning, thinking illusion, inferential
confusion, inverse inference.
