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Anticipation of pleasure - a key aspect of hedonic experience - is a motivating factor for engaging in activities. Low levels of anticipatory pleasure and activity are found in individuals with psychosis. Cognitive factors (e.g., working memory and IQ) have been a focus of explanation for anticipation of pleasure in psychosis. However, cognitive factors do not fully account for such difficulties. It is plausible that emotional factors (e.g., depression, self-beliefs) also contribute. We examined anticipatory pleasure in relation to cognitive and emotional processes in patients with current psychosis. 128 patients with persecutory delusions in the context of non-affective psychosis completed assessments of anticipatory pleasure, cognitive functioning, emotional processes, and activity. Lower anticipatory pleasure was significantly associated with depression, insomnia, negative-self beliefs, suicidal ideation, poorer psychological wellbeing, and paranoia-related avoidance. There were no significant associations with working memory, physical activity, or meaningful activity.  Emotional factors may play a more significant role than cognitive difficulties in the experience of anhedonia in psychosis. However, the cross-sectional design precludes causal inferences. Future research should examine whether, for example, improving self-concept or reducing paranoia-related avoidance leads to improvement in anticipatory pleasure in patients with psychosis., (Copyright © 2020. Published by Elsevier B.V.)

Recent evidence suggests that sleep problems are associated with psychotic like experiences including paranoia. However, the mechanisms underpinning this association are not well understood and thus studies modelling hypothesised mediating factors are required. Alexithymia, the inability to recognise and describe emotions within the self may be an important candidate. In two separate studies we sought to investigate factors mediating the relationship between sleep quality and paranoia using a cross-sectional design. Healthy volunteers without a mental health diagnosis were recruited (study 1, N = 401, study 2, N = 402). Participants completed a series of measures assessing paranoia, negative emotions, alexithymia and perceptual anomalies in an online survey. In study 1, regression and mediation analyses showed that the relationship between sleep quality and paranoia was partially mediated by alexithymia, perceptual anomalies and negative affect. In contrast, study 2 found that the relationship between sleep quality and paranoia was fully mediated by negative affect, alexithymia and perceptual anomalies. The link between sleep quality and paranoia is unclear and reasons for discrepant results are discussed. Novel findings in this study include the link between alexithymia and paranoia., (Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.)

This was a naturalistic study of 23 abstinent cocaine-dependent patients and 38 controls who were studied using a paired-stimulus paradigm to elicit three mid-latency auditory evoked responses (MLAERs), namely, the P50, N100, and P200. Sensory gating was defined as the ratio of the S2 amplitude to the S1 amplitude. Psychosis-proneness was assessed using four Chapman psychosis proneness scales measuring perceptual aberration, magical ideation, social anhedonia, and physical anhedonia. Omnibus correlations based upon the entire sample revealed significant and differential relationships between the MLAER components and psychosis-proneness. Social Anhedonia scale scores accounted for the largest proportion of variance in the P50 gating ratio, while Perceptual Aberration scores accounted for the largest proportion of variance in P200 gating. Psychosis proneness and sensory gating appear to be associated. In particular, poorer P50 gating is related to higher scores on the Social Anhedonia scale in healthy controls and across mixed samples of cocainede-pendent patients and controls. These findings hold significance for the further understanding of the relationship between deficient sensory gating ability and the propensity to developing psychotic symptoms in a vulnerable population like cocaine-dependent individuals., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

This study aimed to explore the validity of an experiment-based paradigm for assessing the suspicious thoughts in healthy volunteers and its corresponding neural process. Twenty-four pairs of healthy college students participated in this study and were randomly assigned to two experimental conditions: the informed (12 pairs) and the naive (12 pairs) conditions. EEG of one subject in each pair was recorded when the 'feeling of being seen through' was evoked. The findings showed a prominent positive deflection of the difference wave within the time window 200 ms-400 ms after stimuli presentation (0 ms) in the naive group. The ERP amplitude of frontal and central scalp sites was significantly different between high and low paranoia rating scores. These findings provide preliminary evidence on the use of an ERP paradigm to detect paranoid ideation or suspicious thoughts in non-clinical sample.

Cocaine-dependence has been shown to affect the amplitudes of the P50 mid-latency auditory evoked response (MLAER) as well as P50 sensory gating. The effects on subsequent MLAERs (N100 and P200) have not been examined. The objective of the current study was to further assess the effects of chronic cocaine use on the P50, N100, and P200 components. Thirty-four, at least three weeks abstinent, cocaine-dependent individuals and 34 age and gender matched healthy controls were examined. The amplitudes, latencies and gating measures were calculated and compared between the groups. The N100 and P200 were significantly smaller in patients as compared to control subjects. Sensory gating of the P50, the N100, and the P200 were deficient in cocaine-dependent subjects. Latencies of all measured components were prolonged in subjects who reported developing paranoia while intoxicated. Finally, a positive correlation was found between length of abstinence and evoked response amplitudes. We conclude that the effects of cocaine on sensory gating extend beyond the P50 to the N100 and the P200 components. The data also suggest that prolonged latency of the evoked potentials may be a correlate of cocaine-induced psychosis. Finally, the data suggest that some recovery of amplitude and gating occurs with abstinence.

Chronic methamphetamine abuse is associated with disruption of frontostriatal function involving serotonin and dopamine circuitry. Clinically, methamphetamine-dependent (MD) individuals are highly distractible and have difficulty focussing. Here, we used a computerized single-trial version of the Stroop Test to examine selective attention and priming in MD. Subject groups comprised eight MD men (31.7+/-7.2 years of age), who had used methamphetamine for 15.75+/-8.4 years but were currently abstinent for 2-4 months, and 12 controls (35.7+9.7 years of age). Compared with the control group, the MD group exhibited significantly greater interference (P<0.05) despite intact priming. Error rates did not differ between the groups. This preliminary finding of reduced cognitive inhibition in MD individuals is consistent with the distractibility they show clinically. Furthermore, the dissociation between explicit attentional performance and priming effects suggests that some attentional functions are not as affected by long-term methamphetamine use as others.