Learned irrelevance and associative learning is attenuated in individuals at risk for psychosis but not in asymptomatic first-degree relatives of schizophrenia patients: translational state markers of psychosis?

Learned irrelevance (LIrr) refers to a form of selective learning that develops as a result of prior noncorrelated exposures of the predicted and predictor stimuli. In learning situations that depend on the associative link between the predicted and predictor stimuli, LIrr is expressed as a retardation of learning. It represents a form of modulation of learning by selective attention. Given the relevance of selective attention impairment to both positive and cognitive schizophrenia symptoms, the question remains whether LIrr impairment represents a state (relating to symptom manifestation) or trait (relating to schizophrenia endophenotypes) marker of human psychosis. We examined this by evaluating the expression of LIrr in an associative learning paradigm in (1) asymptomatic first-degree relatives of schizophrenia patients (SZ-relatives) and in (2) individuals exhibiting prodromal signs of psychosis ("ultrahigh risk" [UHR] patients) in each case relative to demographically matched healthy control subjects. There was no evidence for aberrant LIrr in SZ-relatives, but LIrr as well as associative learning were attenuated in UHR patients. It is concluded that LIrr deficiency in conjunction with a learning impairment might be a useful state marker predictive of psychotic state but a relatively weak link to a potential schizophrenia endophenotype.

[Knowledge, attitude and reservations of medical students about organ transplantation: results of a survey during the first year of study]

AIM: Establish a list of first year medical students' attitudes, doubts, and knowledge in the fields of organ transplantation and donation. METHOD: Anonymized questionnaire handed out to students during class lectures. RESULTS: 183 questionnaires were distributed and 117 returned (participation: 64%). The average age of the students was 21.6 +/- 2.7 years (range 18 to 38 years); the sample included 71 women (60.7%) and 48 men (39.3%). Only 2 students (2%) were not interested in the subject of organ donation. The students knew very little of the legal aspects of organ donation and 1/4 of them thought there was even a Federal law regarding organ transplantation. When asked if they knew whether a law existed in the Canton of Berne, 44% replied yes, but only 24 (20%) knew that this is contradictory. There was no gender difference in the answers to these question. From 57 students (48%) 246 individual comments on doubts and concerns were analyzed. In this respect, the students mainly questioned whether the donor was truly dead when donation took place (n = 48), if illegal transplantation could be eliminated (n = 44) and if transplantation was truly necessary (n = 43). Some also mentioned religious/ethical doubts (n = 42). In regard to organ donation by a living individual, 27 students were concerned about the health of this donor. 20 students had doubts regarding the pressure possibly applied by family members and friends and as many voiced doubts in regard to premature diagnosis of brain death of potential donors. Only 2 students were concerned about the post-mortem presentation. 45 students (48%) indicated discomfort with the donation of certain organs. They ranked the kidney as the first organ to donate, followed by the pancreas, heart, cornea, intestine, lung and liver. CONCLUSION: The interest in organ donation and transplantation is already strong in fist year medical students in the pre-clinical stage. However, differences from lay public are not readably detectable at this stage of medical training. Adequate information could influence future physicians in their mediatory role.