The strengths of this study are the size of the clinical
group, the range of biases studied, and the links made
with the current experience of persecutory thinking.
Testing the patients on 4 affective processes (threat anticipation,
interpretation of ambiguity, self-focus, negative
ideas about self) meant there was no reliance on a single
task. However, the key limitation is the cross-sectional nature of the link made between affect and paranoia.
It could not be determined whether the affective biases
contribute to the future occurrence of paranoia, however
plausible this might seem. It was also not possible
to examine whether the cognitive processes are mediators
of the links between negative affect and paranoia.
Longitudinal study of these processes would be especially
helpful. We did not alter significance levels for multiple
testing, ascribing to the view that “simply describing
what tests of significance have been performed, and why,
is generally the best method of dealing with multiple
comparisons.”46 It was shown that a bias in anticipation
of events only occurred for threatening and not for
positive or neutral events; it would be helpful in future
studies to examine different types of threatening events
(eg, social and nonsocial situations) in order to assess the
generalization of threat anticipation. It would also be
valuable to examine the influence of affective processes
in relation to delusional subtypes.47 Other affective processes,
for instance, worry,12 emotion regulation,48 and
interpersonal sensitivity33 have recently been investigated
in relation to paranoid thinking, and future work needs
to identify those that are key to understanding and therefore
important to target in treatment. Our view is that
treating emotional dysfunction in patients should lead
to reductions in psychotic experiences, and this requires
clinical evaluation.