CONDITIONED BLOCKING IN PATIENTS WITH PARANOID,
NON-PARANOID PSYCHOSIS OR OBSESSIVE
COMPULSIVE DISORDER: ASSOCIATIONS WITH SYMPTOMS,
PERSONALITY AND MONOAMINE METABOLISM
R. D. OADES, B. ZIMMERMANN and C. EGGERS
University Clinic for Child and Adolescent Psychiatry, Virchowstrasse 174, D-45147 Essen, Germany
(Received 29 August 1995; revised 18 January 1996; accepted 29 January 1996)
Summary—Conditioned blocking (CB) refers to a delay in learning that a new stimulus, added
during learning, has the same consequences as the conditioned stimulus already present. In animals
such "learned inattention" depends on monoaminergic and limbic function and, thus, CB per-
formance should be informative on selective information processing impairments found in subgroups
of psychotic patients. Attenuated CB in acute schizophrenia has been reported to normalize rapidly.
This study examines in young patients the specificity of CB performance to illness, and its associ-
ations with symptoms, personality traits and monoaminergic metabolic status. CB was attenuated
in psychotic patients with non-paranoid symptoms (NP: n= 12. mean age 17 years) with respect to
obsessive-compulsive (OCD: и= 13, mean age 16 years) and healthy subjects (CON, n = 29, mean
age 18 years), but only a transient attenuation was observed in paranoid hallucinatory patients (PH:
n—14, mean age 19 years). Outgoing personality traits in CON and OCD subjects correlated with
CB. In NP patients attenuated CB was associated with increasing neurotic lability. In PH patients
CB correlated positively with "manic" but negatively with psychotic or neurotic scores. The severity
of negative symptoms in psychosis and specific negative∕positive symptoms in the NP∕PH groups
was associated with reduced CB. Increased dopamine activity (24-h urine samples) correlated
positively with CB, but relative increases of noradrenaline metabolism in NP and serotonin metab-
olism in OCD patients interfered. In summary, marked psychotic or neurotic traits and some
symptom-states were associated with reduced CB. The particular selective processing problems of
NP patients may reflect inappropriate NA activity. Copyright © 1996 Elsevier Science Ltd.
Introduction
Latent inhibition (Lubow & Moore, 1959) and conditioned blocking (CB, Kamin, 1969)
belong to a paradigm known as learned inattention. If a stimulus (e.g. a light flash) is
repeated several times without consequence before becoming associated with reinforcement,
learning about the relationship initially occurs more slowly than without the non-reinforced
preexposure. This is known as latent inhibition. If the flash is reinforced initially and during
the course of learning a second stimulus is introduced (e.g. a tone, also perfectly correlated
with reinforcement) then learning about the tone is initially slower than if the two stimuli
were contiguous from the start. This is known as CB. In this paper we ask what can studies
of learned inattention tell us about information processing in psychotic patients?
Learned inattention has been related to monoaminergic and limbic function (accumbens-
septum-hippocampus and prefrontal cortex) in animals and its disruption in acute schizo-
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