Conditioned Blocking: Schizophrenia
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(i.e. independent of the two-stimuli Bl condition). This would lead to the prediction of more
learning about the added stimulus and the attenuation of CB. Both styles are reminiscent of
the repetitive structuring of stimulus-response strategies described for chronic schizo-
phrenics by Lyon et al. (1986) and Lyon & Gerlach (1988).
It was this three-stimuli phase, and to an extent the CB result arising from it, that
provided the only correlation to personality scores. The correlation implies that learning
about the added stimulus (i.e. decreased CB) is more likely in the presence of neurotic traits,
as suggested by Jones et al. (1990). This is consistent with reports that those with outgoing
traits cope better with situations requiring parallel processing (see Introduction). This
viewpoint assumes that CB reflects active processing of both stimuli in parallel and that
reduced CB reflects shilling resources between stimuli in series. Oades et al. (1996) reported
that outgoing traits in healthy adults, but not children or adolescents, correlated with the
amount of CB. We were probably unable to replicate this here as our control group
contained subjects selected to match patients under 16 years of age. None the less within
the limited range shown by the largely introverted OCD group, CB showed a modest
correlation with outgoing features.
In the PH group, neurotic lability and psychasthenia scores were high and correlated
negatively with initial CB. This seems compatible with the view that these features are
associated with problems of concentration and indecision (Archer, 1992, p. 194). However,
it may, more specifically, relate to their insensitive exploration patterns, described above,
and to impaired spatial search patterns as described by Jutai (1989) in psychosis-prone
subjects. The rapid development of CB in the PH group, if difficult to explain, recalls the
accelerated cognitive processing reported in an “active” group of patients with similar
symptoms and personality traits by Gruzefier (1991) and Gruzelier et al. (1995). Consistent
with this, our PH patients tended to show more manic features. Interestingly Gruzelier
contrasted this performance with a neuropsychologically-impaired, negative, “withdrawn”
group reminiscent of our NP patients.
Our correlative analysis cannot provide any evidence that attention-related performance
is causally related to personality dimensions, but a number of recent studies have indicated
that personality measures of psychotic-proneness and neuropsychological measures of
attention-related processing may tap similar vulnerabilities (Gruzelier, 1991; Gruzelier et
al., 1995; Jutai, 1989; Franke et al., 1994). Their description thus extends and adds weight
to other findings of interactions between personality traits and learned inattention (see
Introduction).
Psychotic symptoms
Reflecting the symptom state of the two patient groups, the increasing presence of positive
symptoms was related to less of a CB impairment. However, high or low scores on a
particular symptom cluster did not mean that this was or was not important for the
particular function required in the CB test. Symptoms had a differential significance for the
subgroups. Thus, for PH patients bizarre behaviour (modest) and delusions (marked) were
negatively, while hallucinations (marked) and thought disorder (modest) were positively,
associated with CB. Flat-affect and alogia had a generally negative association with CB on
the first few trials, particularly in NP patients for whom symptom severity was important.