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Oades, R.D., Zimmermann, B. & Eggers,
C. (1996) Conditioned blocking in
patients with psychosis and in obsessive compulsive disorder: Association
with symptoms, personality and monoamine metabolism. J. Psychiat.
Res, 30, 369-390. (request
a copy) . (view) .
Introduction:
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 performance 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.
Method:
This study examines in young patients the specificity of CB performance
to illness, and its associations with symptoms, personality traits
and monoaminergic metabolic status.
Results:
Performance: CB was attenuated in psychotic patients
with non-paranoid 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 observed in paranoid hallucinatory
patients (PH: n=14, mean age 19 years). The severity
of negative symptoms in psychosis and specific
negative/positive symptoms in the NP/PH groups were associated with
reduced CB. 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. Monoamines: Increased dopamine
activity (24h urine samples) correlated positively with CB, but relative
increases of noradrenaline metabolism in NP and serotonin metabolism
in OCD patients interfered.
Conclusions:
Marked psychotic or neurotic traits and some negative symptom states
were associated with reduced CB. The particular selective processing
problems of NP patients may reflect inappropriate NA activity.
see also: Oades et al. (1996)
Dev. Neuropsychol. (on normal blocking
and its development)
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