The close anatomical and functional connection between the orbitofrontal cortex and olfactory processing suggests that emotion regulation and olfactory identification could be associated. Smell identification deficit (SID) is common in adult schizophrenia, but it has been less studied in bipolar patients, who also show a significant degree of social disadvantage.

A sample of 27 euthymic bipolar patients were recluted. Euthymia was defined as YMRS < 6 and HDRS < 8, during a 3-month period. Patients were assessed with the University of Pennsylvania Smell Identification Test (UPSIT), Face Recognition Test and a verbal Theory of Mind test (Faux Pas Test), in order to examine the association between olfactory identification ability and social cognition domains.

According to the hypothesis, olfactory identification was positively correlated with Face Emotion Recognition (Pearson, p = 0.007) and verbal Theory of Mind (Pearson, p=0.030). Smell identification was similar in smoker (15/27) and non-smoker subgroup of the sample (U Mann Whitney; p = n.s). No differences were neither found between male (14/27) and female subgroup (U; p = n.s).

Olfactory identification and social cognition (specially, face emotion recognition) appear to represent two correlated traits in bipolar disorder, suggesting a possible common neural substrate.