Book chapters will be unavailable on Saturday 24th August between 8am-12pm BST. This is for essential maintenance which will provide improved performance going forwards. Please accept our apologies for any inconvenience caused.
To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Impaired spatial working memory (SWM) is a robust feature of schizophrenia and has been linked to the risk of developing psychosis in people with an at-risk mental state (ARMS). We used functional magnetic resonance imaging (fMRI) to examine the neural substrate of SWM in the ARMS and in patients who had just developed schizophrenia.
fMRI was used to study 17 patients with an ARMS, 10 patients with a first episode of psychosis and 15 age-matched healthy comparison subjects. The blood oxygen level-dependent (BOLD) response was measured while subjects performed an object–location paired-associate memory task, with experimental manipulation of mnemonic load.
In all groups, increasing mnemonic load was associated with activation in the medial frontal and medial posterior parietal cortex. Significant between-group differences in activation were evident in a cluster spanning the medial frontal cortex and right precuneus, with the ARMS groups showing less activation than controls but greater activation than first-episode psychosis (FEP) patients. These group differences were more evident at the most demanding levels of the task than at the easy level. In all groups, task performance improved with repetition of the conditions. However, there was a significant group difference in the response of the right precuneus across repeated trials, with an attenuation of activation in controls but increased activation in FEP and little change in the ARMS.
Abnormal neural activity in the medial frontal cortex and posterior parietal cortex during an SWM task may be a neural correlate of increased vulnerability to psychosis.
Cognitive models suggest that auditory verbal hallucinations arise through defective self-monitoring and the external attribution of inner speech. We used a paradigm that engages verbal self-monitoring (VSM) to examine whether this process is impaired in people experiencing prodromal symptoms, who have a very high risk of developing psychosis.
We tested 31 individuals with an At-Risk Mental State (ARMS) and 31 healthy volunteers. Participants read single adjectives aloud while the source and pitch of the online auditory verbal feedback was manipulated, then immediately identified the source of the speech they heard (Self/Other/Unsure). Response choice and reaction time were recorded.
When reading aloud with distorted feedback of their own voice, ARMS participants made more errors than controls (misidentifications and unsure responses). ARMS participants misidentified the source of their speech as ‘Other’ when the level of acoustic distortion was severe, and misidentification errors were inversely related to reaction times.
Impaired VSM is evident in people with an ARMS, although the deficit seems to be less marked than in patients with schizophrenia. Follow-up of these participants may clarify the extent to which the severity of this impairment predicts the subsequent onset of psychosis and development of positive symptoms.
Despite the increasing development of early intervention services for psychosis, little is known about their cost-effectiveness. We assessed the cost-effectiveness of Outreach and Support in South London (OASIS), a service for people with an at-risk mental state (ARMS) for psychosis.
The costs of OASIS compared to care as usual (CAU) were entered in a decision model and examined for 12- and 24-month periods, using the duration of untreated psychosis (DUP) and rate of transition to psychosis as key parameters. The costs were calculated on the basis of services used following referral and the impact on employment. Sensitivity analysis was used to test the robustness of all the assumptions made in the model.
Over the initial 12 months from presentation, the costs of the OASIS intervention were £1872 higher than CAU. However, after 24 months they were £961 less than CAU.
This model suggests that services that permit early detection of people at high risk of psychosis may be cost saving.
Cognitive models of psychosis suggest that whether anomalous experiences
lead to clinically relevant psychotic symptoms depends on how they are
appraised, the context in which they occur and the individual's emotional
To develop and validate a semi-structured interview (the Appraisals of
Anomalous Experiences Interview; AANEX) to assess (a) anomalous
experiences and (b) appraisal, contextual and response variables
Following initial piloting, construct validity was tested via
cross-sectional comparison of data from clinical and non-clinical samples
with anomalous experiences. Interrater reliability was also assessed
Scores from AANEX measuring appraisals, responses and social support
differentiated the clinical and nonclinical groups. Interrater
reliability was satisfactory for 65 of the 71 items. Six items were
The AANEX is avalid multidimensional instrument that provides a detailed
assessment of psychotic-like experiences and subjective variables
relevant to the development of a need for clinical care
Cognitive models propose that faulty appraisal of anomalous experiences
is critical in developing psychosis, particularly delusions. A data
gathering bias may be fundamental to abnormal appraisal
To examine whether there is a data gathering bias in people at high risk
of developing psychosis
Individuals with an at-risk mental state (n=35) were
compared with a matched group of healthy volunteers
(n=23). Participants were tested using a modified
version of the ‘beads’ reasoning task with different levels of task
When task demands were high, the at-risk group made judgements on the
basis of less information than the control group (P <
0.05). Within both groups, jumping to conclusions was directly correlated
with the severity of abnormal beliefs and intolerance of uncertainty
(P<0.05). In the at-risk group it was also
associated with impaired working memory (P<0.05),
whereas in the control group poor working memory was associated with a
more conservative response style (P<0.05)
People with an at-risk mental state display a jumping to conclusions
reasoning style, associated with impaired working memory and intolerance
of uncertainty. This may underlie a tendency to develop abnormal beliefs
and a vulnerability to psychosis
Email your librarian or administrator to recommend adding this to your organisation's collection.