Compulsive tendencies are a central feature of problematic human behavior and thereby are of great interest to the scientific and clinical community. However, no consensus exists about the precise... Show moreCompulsive tendencies are a central feature of problematic human behavior and thereby are of great interest to the scientific and clinical community. However, no consensus exists about the precise meaning of ‘compulsivity,’ creating confusion in the field and hampering comparison across psychiatric disorders. A vague conceptualization makes compulsivity a moving target encompassing a fluctuating variety of behaviors, which is unlikely to improve the new dimension-based psychiatric or psychopathology approach. This article aims to help progress the definition of what constitutes compulsive behavior, cross-diagnostically, by analyzing different definitions in the psychiatric literature. We searched PubMed for articles in human psychiatric research with ‘compulsive behavior’ or ‘compulsivity’ in the title that focused on the broader concept of compulsivity—returning 28 articles with nine original definitions. Within the definitions, we separated three types of descriptive elements: phenomenological, observational and explanatory. The elements most applicable, cross-diagnostically, resulted in this definition: Compulsive behavior consists of repetitive acts that are characterized by the feeling that one ‘has to’ perform them while one is aware that these acts are not in line with one’s overall goal. Having a more unified definition for compulsive behavior will make its meaning precise and explicit, and therefore more transferable and testable across clinical and non-clinical populations. Show less
Yücel, M.; Oldenhof, E.; Ahmed, S.; Belin, D.; Billieux, J.; Bowden-Jones, H.; ... ; Verdejo-Garcia, A. 2019
Creativity is a compelling but heterogeneous phenomenon. As opposed to big-C creativity, which is regarded as limited to the rare brilliant mind, little-c creativity is indispensable in adaptive... Show moreCreativity is a compelling but heterogeneous phenomenon. As opposed to big-C creativity, which is regarded as limited to the rare brilliant mind, little-c creativity is indispensable in adaptive everyday behavior, serving to adjust to changing circumstances and challenges. Computational approaches help demystify human creativity by offering insights into the underlying mechanisms and their characteristics. Recently proposed computational models to creative cognition often focus on either divergent or convergent problem-solving, but some start to integrate these processes into broader cognitive frameworks. We briefly review the state-of-the-art in the field and point out theoretical overlap. We extract basic principles that most existing models agree on and desiderata on the way towards a comprehensive model. Show less
Cognitive control requires a balance between persistence and flexibility. We studied inter- and intraindividual differences in the metacontrol bias towards persistence or flexibility in cognitive... Show moreCognitive control requires a balance between persistence and flexibility. We studied inter- and intraindividual differences in the metacontrol bias towards persistence or flexibility in cognitive search tasks from various cognitive domains that require continuous switching between persistence and flexibility. For each task, clustering and switching scores were derived to assess persistence and flexibility, respectively, as well as a total performance score to reflect general performance. We compared two, not mutually exclusive accounts according to which the balance between clustering and switching scores is affected by (1) individual, trait-like metacontrol biases towards persistence or flexibility and/or (2) the metacontrol adaptivity to bias states according to changing situational demands. We found that clustering and switching scores failed to generalize across tasks. However, clustering and switching were inversely related and predicted the total performance scores in most of the tasks, which in turn partially generalized across tasks and task domains. We conclude that metacontrol-biases towards persistence or flexibility can be adapted easily to specific task demands and individual resources, possibly overwriting individual metacontrol trait biases. Moreover, we suggest that total performance scores might serve to measure metacontrol adaptivity in future studies if task-restrictions and resources are known and/or well balanced. Show less
Yücel, M.; Oldenhof, E.; Ahmed, S.H.; Belin, D.; Billieux, J.; Bowden-Jones, H.; ... ; Verdejo-Garcia, A. 2018
BackgroundThe US National Institutes of Mental Health Research Domain Criteria (RDoC) seek to stimulate research into biologically validated neuropsychological dimensions across mental illness... Show moreBackgroundThe US National Institutes of Mental Health Research Domain Criteria (RDoC) seek to stimulate research into biologically validated neuropsychological dimensions across mental illness symptoms and diagnoses. The RDoC framework comprises 39 functional constructs designed to be revised and refined, with the overall goal of improving diagnostic validity and treatments. This study aimed to reach a consensus among experts in the addiction field on the ‘primary’ RDoC constructs most relevant to substance and behavioural addictions.MethodsForty‐four addiction experts were recruited from Australia, Asia, Europe and the Americas. The Delphi technique was used to determine a consensus as to the degree of importance of each construct in understanding the essential dimensions underpinning addictive behaviours. Expert opinions were canvassed online over three rounds (97% completion rate), with each consecutive round offering feedback for experts to review their opinions.ResultsSeven constructs were endorsed by ≥ 80% of experts as ‘primary’ to the understanding of addictive behaviour: five from the Positive Valence System (reward valuation, expectancy, action selection, reward learning, habit); one from the Cognitive Control System (response selection/inhibition); and one expert‐initiated construct (compulsivity). These constructs were rated to be related differentially to stages of the addiction cycle, with some linked more closely to addiction onset and others more to chronicity. Experts agreed that these neuropsychological dimensions apply across a range of addictions.ConclusionsThe study offers a novel and neuropsychologically informed theoretical framework, as well as a cogent step forward to test transdiagnostic concepts in addiction research, with direct implications for assessment, diagnosis, staging of disorder, and treatment. Show less
IntroductionTaking microdoses (a mere fraction of normal doses) of psychedelic substances, such as truffles, recently gained popularity, as it allegedly has multiple beneficial effects including... Show moreIntroductionTaking microdoses (a mere fraction of normal doses) of psychedelic substances, such as truffles, recently gained popularity, as it allegedly has multiple beneficial effects including creativity and problem-solving performance, potentially through targeting serotonergic 5-HT2A receptors and promoting cognitive flexibility, crucial to creative thinking. Nevertheless, enhancing effects of microdosing remain anecdotal, and in the absence of quantitative research on microdosing psychedelics, it is impossible to draw definitive conclusions on that matter. Here, our main aim was to quantitatively explore the cognitive-enhancing potential of microdosing psychedelics in healthy adults.MethodsDuring a microdosing event organized by the Dutch Psychedelic Society, we examined the effects of psychedelic truffles (which were later analyzed to quantify active psychedelic alkaloids) on two creativity-related problem-solving tasks: the Picture Concept Task assessing convergent thinking and the Alternative Uses Task assessing divergent thinking. A short version of the Ravens Progressive Matrices task assessed potential changes in fluid intelligence. We tested once before taking a microdose and once while the effects were expected to be manifested.ResultsWe found that both convergent and divergent thinking performance was improved after a non-blinded microdose, whereas fluid intelligence was unaffected.ConclusionWhile this study provides quantitative support for the cognitive-enhancing properties of microdosing psychedelics, future research has to confirm these preliminary findings in more rigorous placebo-controlled study designs. Based on these preliminary results, we speculate that psychedelics might affect cognitive metacontrol policies by optimizing the balance between cognitive persistence and flexibility. We hope this study will motivate future microdosing studies with more controlled designs to test this hypothesis. Show less
Sjoerds, Z.; Stufflebeam, S.M.; Veltman, D.J.; Brink, W. van den; Penninx, B.W.; Douw, L. 2015
Alcohol dependence (AD) is characterized by corticostriatal impairments in individual brain areas such as the striatum. As yet however, complex brain network topology in AD and its association with... Show moreAlcohol dependence (AD) is characterized by corticostriatal impairments in individual brain areas such as the striatum. As yet however, complex brain network topology in AD and its association with disease progression are unknown. We applied graph theory to resting‐state functional magnetic resonance imaging (RS‐fMRI) to examine weighted global efficiency and local (clustering coefficient, degree and eigenvector centrality) network topology and the functional role of the striatum in 24 AD patients compared with 20 matched healthy controls (HCs), and their association with dependence characteristics. Graph analyses were performed based on Pearson's correlations between RS‐fMRI time series, while correcting for age, gender and head motion. We found no significant group differences between AD patients and HCs in network topology. Notably, within the patient group, but not in HCs, the whole‐brain network showed reduced average cluster coefficient with more severe alcohol use, whereas longer AD duration within the patient group was associated with a global decrease in efficiency, degree and clustering coefficient. Additionally, within four a‐priori chosen bilateral striatal nodes, alcohol use severity was associated with lower clustering coefficient in the left caudate. Longer AD duration was associated with reduced clustering coefficient in caudate and putamen, and reduced degree in bilateral caudate, but with increased eigenvector centrality in left posterior putamen. Especially changes in global network topology and clustering coefficient in anterior striatum remained strikingly robust after exploratory variations in network weight. Our results show adverse effects of AD on overall network integration and possibly on striatal efficiency, putatively contributing to the increasing behavioral impairments seen in chronically addicted patients. Show less
Sjoerds, Z.; Brink, W. van den; Beekman, A.T.F.; Penninx, B.W.J.H.; Veltman, D.J. 2014
BACKGROUND: A family history (FH) of alcohol dependence (AD) not only increases the risk for AD, but is also associated with an increased risk for mood and anxiety disorders. However, it is unknown... Show moreBACKGROUND: A family history (FH) of alcohol dependence (AD) not only increases the risk for AD, but is also associated with an increased risk for mood and anxiety disorders. However, it is unknown how a FH of AD affects neural substrates in patients with mood and anxiety disorders. In this study we examined the effects of an alcoholic FH on cognitive and emotional functions in these patients using functional magnetic resonance imaging (fMRI). Method In a sample of non-alcoholic patients with depressive and/or anxiety disorders from the Netherlands Study of Depression and Anxiety (NESDA) neuroimaging study, patients with a first-degree FH of AD (FH + ; n = 31) were compared with patients without a FH (FH-; n = 77) on performance and brain activation during visuospatial planning and emotional word encoding. Results were compared with those of healthy controls (HCs) without a FH of AD (n = 31). RESULTS: FH+ patients performed slower during planning with increasing task load, coupled with stronger blood oxygen level-dependent responses in dorsal prefrontal areas compared with FH- patients and HCs. FH was not associated with performance differences during word encoding, but right insula activation during positive word encoding was present in FH+ patients, comparable with HCs, but absent in FH- patients. CONCLUSIONS: This study demonstrates subtle impairments during planning in FH+ compared with FH- patients and HCs, whereas activation during mood-incongruent stimuli in FH+ patients was similar to HCs but not FH- patients, suggesting that the presence of a FH of AD is a useful marker for the neurophysiological profile in mood/anxiety disorders and possible predictor for treatment success. Show less
Sjoerds, Z.; Tol, M.J. van; Brink, W. van den; Wee, N.J.A. van der; Buchem, M.A. van; Aleman, A.; ... ; Veltman, D.J. 2012
Objectives. Alcohol-use disorders in adolescents are associated with gray matter (GM) abnormalities suggesting neurotoxicity by alcohol. However, recently similar GM abnormalities were found in non... Show moreObjectives. Alcohol-use disorders in adolescents are associated with gray matter (GM) abnormalities suggesting neurotoxicity by alcohol. However, recently similar GM abnormalities were found in non-drinking children with a family history (FH) of alcohol dependence (AD). The question thus rises whether these abnormalities represent a transient delay in brain maturation or a persistent risk factor for developing neuropsychiatric disorders, rather than a (neurotoxic) consequence of AD. This study investigated whether a FH of AD in non-drinking adults is associated with abnormal GM-volumes similar to those observed in drinking and non-drinking adolescents with a FH of AD. Methods. GM-images were analyzed using Voxel-Based Morphometry in non-alcoholics with (FH+; N = 36) and without (FH-; N = 107) familial AD. Additionally we controlled for possible confounders: diagnosis of depression/anxiety, childhood trauma and familial depression/anxiety. Results. Smaller GM-volumes were shown in the right parahippocampal gyrus in FH+ compared with FH-. Results were unaffected by confounders. Conclusions. We demonstrated an effect of familial AD in non-alcoholic adults on GM volume in the parahippocampal gyrus, similar to drinking and non-drinking FH+ adolescents. These findings suggest that GM abnormalities in the parahippocampal gyrus represent a persistent biological susceptibility for AD or related psychopathology and not neurotoxicity of alcohol or delayed brain maturation. Show less
