ORCID Profile
0000-0003-3974-2362
Current Organisation
Monash University
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Publisher: Wiley
Date: 25-07-2019
DOI: 10.1111/EJN.13961
Abstract: Animal studies have demonstrated that chronic exposure to drugs of abuse impairs goal-directed control over action selection indexed by the outcome-devaluation and specific Pavlovian to instrumental transfer procedures, suggesting this impairment might underpin addiction. However, there is currently only weak evidence for impaired goal-directed control in human drug users. Two experiments were undertaken in which treatment-seeking drug users and non-matched normative reference s les (controls) completed outcome-devaluation and specific Pavlovian to instrumental transfer procedures notionally translatable to animal procedures (Experiment 2 used a more challenging biconditional schedule). The two experiments found significant outcome-devaluation and specific Pavlovian to instrumental transfer effects overall and there was no significant difference between groups in the magnitude of these effects. Moreover, Bayes factor supported the null hypothesis for these group comparisons. Although limited by non-matched group comparisons and small s le sizes, the two studies suggest that treatment-seeking drug users have intact goal-directed control over action selection, adding uncertainty to already mixed evidence concerning the role of habit learning in human drug dependence. Neuro-interventions might seek to tackle goal-directed drug-seeking rather than habit formation in drug users.
Publisher: Informa UK Limited
Date: 04-03-2022
Publisher: Routledge
Date: 29-12-2020
Publisher: Informa UK Limited
Date: 29-10-2019
Publisher: Elsevier BV
Date: 05-2023
Publisher: Informa UK Limited
Date: 18-02-2020
Publisher: Wiley
Date: 24-08-2022
DOI: 10.1002/JCLP.23420
Abstract: Our study aimed to develop and provide a preliminary psychometric validation of the Somatomorphic Matrix-Female (SM-F), a new bidimensional female figural rating scale which can be used to gauge actual and desired levels of both body fat and muscularity in a consolidated measure, as well as providing an index of actual-desired body discrepancy based on these measures. Across two studies undergraduate women (n Study 1 = 481 n Study 2 = 391) completed the Eating Disorder Examination-Questionnaire, the Body Shape Questionnaire-34, and the Depression Anxiety Stress Scales-21 (Study 1) and the Drive for Thinness Scale and the Drive for Muscularity Scale (Study 2), as well as the SM-F. Overall, the SM-F demonstrated sound content, concurrent, and convergent validity for actual and desired body fat, actual and desired muscularity, and their respective discrepancy scores.
Publisher: Informa UK Limited
Date: 06-2018
DOI: 10.1111/AP.12293
Publisher: Frontiers Media SA
Date: 15-05-2019
Publisher: Springer Science and Business Media LLC
Date: 13-11-2019
DOI: 10.1007/S00426-019-01266-3
Abstract: Pavlovian-to-instrumental transfer (PIT) tasks assess the impact of environmental stimuli on instrumental actions. Since their initial translation from animal to human experiments, PIT tasks have provided insight into the mechanisms that underlie reward-based behaviour. This review first examines the main types of PIT tasks used in humans. We then seek to contribute to the current debate as to whether human PIT effects reflect a controlled, goal-directed process, or a more automatic, non-goal-directed mechanism. We argue that the data favour a goal-directed process. The extent to which the major theories of PIT can account for these data is then explored. We discuss a number of associative accounts of PIT as well as dual-process versions of these theories. Ultimately, however, we favour a propositional account, in which human PIT effects are suggested to be driven by both perceived outcome availability and outcome value. In the final section of the review, we present the potential objections to the propositional approach that we anticipate from advocates of associative link theories and our response to them. We also identify areas for future research.
Publisher: Informa UK Limited
Date: 09-01-2019
Publisher: Springer Science and Business Media LLC
Date: 27-07-2017
DOI: 10.1007/S00221-017-5046-9
Abstract: Substance dependence is thought to be mediated by abnormalities in cognitive abilities, but how this impacts decision-making remains unclear. This study aimed to test whether people who are opiate dependent differed from never-dependent controls in learning from reward and punishment or in the generalization of learning to novel conditions. Participants with opiate dependency consisted of 21 people who were outpatients in a methadone maintenance program the control group consisted of 21 healthy participants with no histories of substance abuse. Subjects completed a computer-based task that involved two phases: the training phase involved participants being presented with compound stimulus (a shape and color) in each trial, with the goal of learning which compounds to 'pick' for rewards or 'skip' to avoid punishment. The test phase involved a transfer test, where stimuli from the first phase were combined together to form novel compounds without feedback. The control group demonstrated fewer errors compared to opiate-dependent in iduals during the training phase. In the test phase, controls used prior knowledge of both shapes and colors in responding however, opiate-dependent in iduals used shapes but did not use their knowledge of color to modulate responding. When performance during training was equated in the groups using a learning threshold, this difference between groups on the generalization test remained. A deficit in learning generalization might be indicative of group differences in learning strategies in operation during training however, future work is necessary to uncover the specific neural substrates in action during transfer tasks, and to determine the effects of acute methadone dosage on decision-making.
Publisher: Walter de Gruyter GmbH
Date: 06-2016
DOI: 10.1515/REVNEURO-2015-0060
Abstract: Introduction: Schizophrenia is a severe mental disorder with multiple psychopathological domains being affected. Several lines of evidence indicate that cognitive impairment serves as the key component of schizophrenia psychopathology. Although there have been a multitude of cognitive studies in schizophrenia, there are many conflicting results. We reasoned that this could be due to in idual differences among the patients (i.e. variation in the severity of positive vs. negative symptoms), different task designs, and/or the administration of different antipsychotics. Methods: We thus review existing data concentrating on these dimensions, specifically in relation to dopamine function. We focus on most commonly used cognitive domains: learning, working memory, and attention. Results: We found that the type of cognitive domain under investigation, medication state and type, and severity of positive and negative symptoms can explain the conflicting results in the literature. Conclusions: This review points to future studies investigating in idual differences among schizophrenia patients in order to reveal the exact relationship between cognitive function, clinical features, and antipsychotic treatment.
Publisher: Springer International Publishing
Date: 21-07-2018
Publisher: Informa UK Limited
Date: 04-05-2018
Publisher: SAGE Publications
Date: 23-03-2019
Abstract: The investigation of psychosocial factors in relation to opiate addiction is limited and typically uses binary measures to assess how incidences of childhood trauma correlate with addiction. There has also been a lack of enquiry into how experiences of noninterpersonal versus interpersonal trauma may impact drug use addiction. In this regard, the current study utilized a novel measurement of interpersonal versus noninterpersonal lifetime trauma and a scale assessing severity of childhood trauma to examine how these factors may impact patients with opioid addiction. The interaction between these factors and current perceived stress was also examined. Thirty-six opioid-dependent in iduals (recruited from the Drug Health Services and Opioid Treatment Program at the Royal Prince Alfred Hospital in Sydney, Australia) and 33 healthy controls completed the Childhood Maltreatment Questionnaire, Lifetime Trauma Survey, and Perceived Levels of Stress Scale. The patient group reported significantly greater childhood trauma severity, more incidences of lifetime trauma, and higher perceived stress than controls. Logistic regression analyses indicated that the severity of childhood trauma was more strongly associated with addiction status than perceived stress. A greater number of lifetime trauma incidence was the best predictor of addiction. Contrary to expectations, noninterpersonal lifetime trauma was a better predictor of addiction status than was interpersonal lifetime trauma. Results suggest that lifetime trauma and childhood trauma may play an important factor in opioid addiction over what can be accounted for by stress.
Publisher: Informa UK Limited
Date: 12-02-2021
Publisher: Informa UK Limited
Date: 18-09-2018
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.PSYCHRES.2018.05.054
Abstract: Recent studies suggest a higher threshold number of self-injuries during the past year than the one proposed in the DSM-5 criteria for non-suicidal self-injury disorder (NSSID). Therefore, we aimed to test a validity of the frequency criterion in girls with conduct disorder (CD) based on psychopathology and the level of functioning. Mixture modelling analysis revealed that the frequency of at least 8 self-harm behaviours in the previous year differentiated adolescents with CD. Thus, we ided adolescents into three subgroups: group 1: at least 8 self-harm acts group 2: 1-7 self-harm behaviours and group 3: those who did not injure themselves during the last 12 months. In iduals from group 1 were significantly younger and had earlier age of self-harm onset. There were significant differences between groups 1 and 3 in terms of anxiety and depressive symptoms, self-esteem, aggression and the global functioning level. The group 1 scored significantly higher on depressive symptoms compared to the group 2. The group 2 scored significantly higher than the group 3 on the level of hostility. Our results provide further evidence supporting the need for modification of the NSSID frequency criterion.
Publisher: Informa UK Limited
Date: 07-2019
DOI: 10.1111/CP.12169
No related grants have been discovered for Justin Mahlberg.