German Journal of Psychiatry    ISSN 1455-1033

2000, Vol. 3, Supplement 1, S7

 

Impaired conditional discrimination learning in patients with social phobia

Sachs G, Anderer P, Eberstaller M, Saletu B, Dantendorfer K.

Department of Psychiatry, University of Vienna, Austria

 

Background: An eyelid conditional discrimination learning (ECDL)  task, which has been shown to selectivly test temporal lobe function, was used to examine unconscious discrimination learning capacity in social phobia (SP) patients to test the hypothesis that in SP the ability to differentiate between significant (i.e.dangerous) and unsignificant stimuli could be impaired.

Methods: 25 unmedicated SP patients (mean age 29.5±7.0)  diagnosed according to DSM-IV criteria and 25 gender and age matched healthy controls (HC) (mean age 34.0±8.6) were examined. In the ECDL  experiment two differently colored stimuli are randomly presented. Only one of the stimuli is followed by an aversive airpuff to the cornea ( a „reinforced trial“) as opposed to „unreinforced trials“ not followed by an airpuff. Conditioned responses (CR; reflectory eyelid closures already upon light presentation) were scored separately for both trial types.

Results: HC as well as SP patients showed a significant difference between reinforced and unreinforced trials (p=.008 and p=0.017 for HC and SP, respectively). However, HC were superior in discrimination ability as compared to SP for reinforced trials (p=.039). Concerning discrimination learning HC steadily increased CR frequency on reinforced trials during the course of the experiment but in SP patients, CR frequency did not increase during ECDL task. Thus SP patients were not able to benefit from the information contained in the task

Conclusions: This is the first experimental study showing that there is a reduced discrimination learning capacity in SP patients. As was shown in a previous study panic disorder patients failed to develop any conditional discrimination ability, therefore in SP patients impairment lies between normal controls and panic disorder patients. Similar to preliminary neuroimaging results our study points out further evidence for temporal lobe dysfunction in SP.