Inference Based Approach, treatment for paranoia *
A replicated randomized single-case A-B-phase design

According to Freeman paranoia is having unfounded thoughts that others are
deliberately intending to cause harm (Freeman, 2016). Paranoia is common in the
general population, at least 10-15% of the people experience paranoid thoughts
(Freeman, 2007). This varies from mistrust and suspiciousness to persecutory
delusions. Persecutory delusions are the severest within the paranoia spectrum
and it is a frequent symptom in psychosis. More than 70% of the patients with a
first psychosis experience persecutory delusions (Coid et al., 2013) and at
least 50% of the people with schizophrenia (Sartorius et al., 1986; Cutting,
1997 cited in Green et al., 2008). Paranoia can be severe and lead to being
withdrawn from social activity, distress, fear, anxiety and lower quality of
life (Freeman, 2016).

The available research on the treatment for psychosis (generally also aiming to
decrease paranoia) shows in general a medium effect-size for either
pharmacotherapy or Cognitive Behavioural Therapy (CBT). More effective
treatment options for patients with paranoia are sorely needed.

The Inference Based Approach (IBA) might be a promising alternative. IBA is an
effective treatment for patients with OCD, especially for patients with OCD
with poor insight (O* Conner et al., 2016; Visser et al., 2015). IBA is based
on the assumption that people with OCD misjudge the actual state of affairs and
therefore feel the need to perform compulsions (H. Visser, et al., 2015). The
patient gives credibility to doubt that comes from imagination and fail to
integrate sensory information in their decision making processes. IBA teaches
patients to rely on sensory information in the here and now.

It is, for various reasons, argumented and hypothesized that IBA is a possible
effective treatment for paranoia. First of all, a person with paranoia has the
perception that he is currently in danger, even when there is no real threat.
IBA teaches the patient to recognize the differences between being absorbed in
imagination and relying on reality information. Another reason why IBA might be
an effective treatment is that paranoia thrives when odd internal sensations
and perceptions provoke fearful explanations (presumably the peculiar narrative
mentioned above). The high physiological arousal associated with anxiety is
mistaken to indicate external threat (Freeman, 2016). IBA teaches the patient
to rely on his senses and not on the imagination of a fearful state.
Because IBA aims at improving reality testing and seems to be especially
effective for OCD with poor or absent insight, which in fact is difficult to
distinguish from psychosis it stands to reason that it might be effective for
paranoia to.

This study is a pilot to provide knowledge wether IBA is indeed an effective
treatment for patients suffering from paranoia. It*s the first time worldwide
that IBA will be investigated within this specified population of people
suffering from paranoia.

Primary objectives:
Is IBA an effective treatment for patients with paranoia, that is, does IBA
result in reduction of paranoia symptoms?

Secondary objectives:
Does insight improve after IBA treatment (i.e. insight in psychosis)?

A replicated randomized single-case design.

In such designs, repeated observations are recorded for a single person on the
dependent variable of interest, and the treatment can be considered as one of
the levels of the independent variable. The observations are recorded
repeatedly during a baseline phase (A phase) and an intervention phase (B
phase). Changes during both phases are being compared for each single case.
Phase designs can be randomized by listing all possible intervention start
points and then randomly selecting one of them for conducting the actual
experiment (Michiels & Onghena, 2018).
In the current study, the target symptom is recorded on a daily basis, starting
at inclusion (T0). The start of the B phase will be randomized over 20 possible
assignments in week 2-5 after T0. This way the guidelines of Kratochwill and
colleagues (2010) are met.

IBA intervention for 20 weekly sessions of 45 minutes.

In IBA treatment patients try to discover that in the situations in which they
experience anxiety and/or anger related to suspiciousness, a peculiar
overwhelming narrative (that is typically a narrative consisting of aberrant
reasoning processes) pops up in their mind and overrules integration of sensory
information. And they learn that this is qualitatively very different from
their general frame of mind (active whenever they experience no
suspiciousness). They learn to anticipate on getting absorbed in those kind of
narratives, that is to recognize and to stop and wait at the moment on which
naturally relying on *here and now sensory information* transposes to relying
on imagination. The patient further learns to defend him- or herself against
the absorbing effect of imagination by recognizing the typical aberrant
reasoning processes and discovering how each of it overrules perception. This
way the patient with paranoia can learn that there is no real threat in the
here and now and therefore no need for anxiety, anger and safety behaviour.

Burden associated with participation during the 'study-intake'
- During the study-intake a semi-structured interview (SCID) will be conducted
and the patient fill in the Green Paranoid Thoughts Scale (GPTS) the Insight
Scale for psychosis (PI). In total, with the informed consent procedure and
explaining the study it will takes about 60 minutes.

Burden associated with the baseline phase (phase A)
- Participant will fill-in the State Social Paranoia Scale (SSPS) on a daily
basis.This takes about 2-3 minutes. The baseline phase depends on the
randomization of the startpoint of the treatment. This can vary between week 2
and week 5.

Burden associated with the treatment phase
- At the start of the treatment the patient will fill in the GPTS and the PI.
- Participants will fill-in the SSPS on a daily basis
- IBA intervention for 20 weekly sessions of 45 minutes.
- At the end of the treatment the patient will fill-in the GPTS and the PI.

Follow-up
- The patient will fill-in the GPTS and the PI.

Anticipated risk factors:*
1. Distress from receiving IBA treatment*Subjects may experience distress,
anxiety or fatigue during IBA treatment, which can be expected by undergoing
any form of psychotherapy. However, we expect no additional risk factors when
compared to CBT, the standard clinical care.
2. Distress from study assessments and questionnaires.