CONDITIONED BLOCKING IN PATIENTS WITH PARANOID, NONPARANOID PSYCHOSISOR OBSESSIVE-COMPULSIVE DISORDER - ASSOCIATIONS WITH SYMPTOMS, PERSONALITY AND MONOAMINE METABOLISM

Conditioned blocking (CB) refers to a delay in learning that a new sti mulus, added during learning, has the same consequences as the conditi oned stimulus already present. In animals such ''learned inattention'' depends on monoaminergic and limbic function and, thus, CB performanc e should be informative on selective information processing impairment s found in subgroups of psychotic patients. Attenuated CB in acute sch izophrenia has been reported to normalize rapidly. This study examines in young patients the specificity of CB performance to illness, and i ts associations with symptoms, personality traits and monoaminergic me tabolic status. CB was attenuated in psychotic patients with non-paran oid symptoms (NP: n = 12, mean age 17 years) with respect to obsessive -compulsive (OCD: n = 13, mean age 16 years) and healthy subjects (CON , n = 29, mean age 18 years), but only a transient attenuation was obs erved in paranoid hallucinatory patients (PH: n = 14, mean age 19 year s). Outgoing personality trails in CON and OCD subjects correlated wit h CB. In NP patients attenuated CB was associated with increasing neur otic lability. In PH patients CB correlated positively with ''manic'' but negatively with psychotic or neurotic scores. The severity of nega tive symptoms in psychosis and specific negative/positive symptoms in the NP/PH groups was associated with reduced CB. Increased dopamine ac tivity (24-h urine samples) correlated positively with CB, but relativ e increases of noradrenaline metabolism in NP and serotonin metabolism in OCD patients interfered. In summary, marked psychotic or neurotic traits and some symptom-states were associated with reduced CB. The pa rticular selective processing problems of NP patients may reflect inap propriate NA activity. Copyright (C) 1996 Elsevier Science Ltd.