Conditioned Blocking: Schizophrenia
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patients, who showed lower NA metabolism than any other group, decreasing NA utili-
zation tended to be associated with increasing CB (BA 1-3, unblocking; r= — .5 to — .6,
.l<∕><,05). 5HT utilization (5HIAA∕5HT) tended to increase with decreased CB on the
unblocking measure alone in the OCD group (r = — 0.58, p < .06). In view of the widespread
finding of unusual 5HT (and sometimes DA) activity in OCD patients, the correlation of
unblocking with increased HVA∕5HIAA is of interest (Figure 6).
There were a number Ofcorrelations for the status of DA metabolism and its relation to
NA and 5HT metabolites (Figure 6). In controls increasing DA metabolism and its relation
to NA metabolism was associated with increased CB. For OCD patients the relationship
to HVA was less marked, but Uke the control group an increase with respect to NA
metabolism correlated with CB. In contrast, the NP group showed a negative association
with HVA∕MHPG (Figure 6). CB did not clearly relate to any biochemical measure in the
PH group (but see Figure 6).
Pursuing these correlations in a linear regression for the four HVA and HVA ratio
measures supports a major role for DA metabolism in the CB shown by controls. The
utilization measure alone was significant (+ .65, ρ = .001). Stepwise regression for three CB
measures leaving DA utilization in the equation attained 5% significance or better (BA 1,
+ .63; BA 1-3, +.40). In OCD patients linear regression showed that the significance of
NA or 5HT metabolism relative to DA was lost with their HVA∕metabolite ratios in the
equation. This confirms the dominant role of DA metabolism (i.e. increased HVA with
increased CB).
In contrast to the PH group where no biochemical measure related to CB, in the NP
Pearson correlations for 3 measures Ofconditioned blocking
in 4 subject groups with the status of DA metabolism and its
Figure 6. (Left) Early CB measures (BA 1, BA 1-3) in both comparison groups correlated positively with DA
metabolism and its relation with NA metabolism (*p < .05). OCD patients also showed a correlation with the
relation of DA to 5HT metabolism (#p<.01). (Right) In the NP group CB correlated negatively with the
HVA∕MHPG ratio (p<.05, #/><.001). Correlations for PH patients were not significant. HVA= 1.7 (CON,
n = 29), 2.6 (OCD, и= 11), 2.1 (PH, n = 12), 1.7 (NP, n=10) mg/nɪg creatinine∕m2 body area. HVA∕DA,
HVA∕MHPG, HVA∕5HIAA ratios=9.2/3.6/10.6 (CON), 10.6/9.1/3.5 (OCD), 15.8/3.7/5.2 (PH). 13.6/5.2/10,2
(NP).