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Background: Cannabis use is prevalent among college students and is associated with negative consequences and cannabis use disorder. Cannabis expectancies (i.e. anticipated effects from using) are integral to cannabis use models and are related to cannabis use outcomes and cannabis motives (i.e. specific reasons for use). However, research has traditionally examined expectancy relations using variable-centered approaches that emphasize higher-order expectancies, despite evidence that expectancies are heterogeneous and comprised of lower-order domains. The current study employed a person-centered approach to identify subgroups of undergraduates who use cannabis from lower-order expectancies and cannabis use behaviors, and subgroup differences across negative consequences, cannabis use disorder risk, and motives were examined. Method: A multisite sample of undergraduates (N = 1148) completed questionnaires regarding cannabis use, expectancies, motives, negative consequences, and cannabis use disorder risk. Results: Latent profile analysis suggested that a six-profile solution best fit the data: profile 1 (low use/very weak expectancies, 9.0%); profile 2 (low use/moderate expectancies, 27.3%); profile 3 (low-moderate use/weak positive expectancies, 17.2%); profile 4 (low-moderate use/strong positive expectancies, 20.6%); profile 5 (moderate use/very strong expectancies, 6.5%); profile 6 (very high use/moderate expectancies, 19.3%). Profiles differed on all outcomes, and those with the strongest expectancies and highest use (profiles 5 and 6) endorsed more negative consequences, risk for cannabis use disorder, and higher levels of motives. Discussion: Findings align with motivational models of cannabis use and suggest that expectancies may be a relevant cannabis use risk marker. Intervention efforts may be enhanced by screening for expectancies, as well as by attempting to modify these expectancies. [ABSTRACT FROM AUTHOR]

Borderline personality disorder (BPD) is characterized by affective, interpersonal, and identity instability, as well as marked impulsivity. There is evidence that BPD may be best operationalized dimensionally using models such as the Alternative Model for Personality Disorders (AMPD) described in Section III of the Diagnostic and Statistical Manual for Mental Disorders (DSM). Moreover, biosocial theory is a well‐known etiological theory of BPD emphasizing emotion dysregulation, inherited impulsivity, and development within invalidating contexts as key etiological mechanisms. Given that current research and clinical efforts for BPD are informed by both nosology and etiology, this narrative review examined how well biosocial theory (a) aligns with AMPD conceptualizations, (b) accounts for psychiatric comorbidity, and (c) accounts for heterogeneity in BPD presentation. Findings suggested that tenets of biosocial theory align well with Criteria A and B of the AMPD; however, biosocial theory focuses narrowly on roles of emotion dysregulation, impulsivity, and invalidating contexts, and empirical support is lacking in some ways for several etiological explanations proposed by biosocial theory. Additionally, although biosocial theory captures empirically supported features of BPD and emphasizes high‐risk subgroups, the theory may not account for lower‐risk subgroups. Finally, the theory accounts for diagnostic co‐occurrence via the central role of emotion dysregulation, but biosocial theory may not be specific to BPD and may broadly apply to a range of psychopathology. Based on the literature reviewed, implications for future research and clinical efforts are highlighted. [ABSTRACT FROM AUTHOR]

Background: Tau aggregation demonstrates close associations with hypometabolism in Alzheimer's disease (AD), although differing pathophysiological processes may underlie their development. Objective: To establish whether tau deposition and glucose metabolism have different trajectories in AD progression and evaluate the utility of global measures of these pathological hallmarks in predicting cognitive deficits. Methods: 279 participants with amyloid-β (Aβ) status, and T1-weighted MRI scans, were selected from the Alzheimer's Disease Neuroimaging Initiative (). We created the standard uptake value ratio images using Statistical Parametric Mapping 12 for [18F]AV1451-PET (tau) and [18F]FDG-PET (glucose metabolism) scans. Voxel-wise group and single-subject level SPM analysis evaluated the relationship between global [18F]FDG-PET and [18F]AV1451-PET depending on the Aβ status. Linear models assessed whether tau deposition or glucose metabolism better predicted clinical progression. Results: There was a dissociation between global cerebral glucose hypometabolism and global tau load in amyloid-positive AD and amyloid-negative mild cognitive impairment (MCI) (p > 0.05). Global hypometabolism was only associated with global cortical tau in amyloid-positive MCI. Voxel-level single subject tau load better predicted neuropsychological performance, Alzheimer's disease assessment scale-cognitive (ADAS-Cog) 13 score, and one-year change compared with regional and global hypometabolism. Conclusions: A dissociation between tau pathology and glucose metabolism at a global level in AD could imply that other pathological processes influence glucose metabolism. Furthermore, as tau is a better predictor of clinical progression, these processes may have independent trajectories and require independent consideration in the context of therapeutic interventions. [ABSTRACT FROM AUTHOR]

Background: Neuroinflammation is a key component of Alzheimer's Disease (AD) pathology. Triggering receptor expressed on myeloid cells 2 (TREM2) is crucial to microglial involvement in AD, mediating trem2‐dependent activation and Disease‐Associated Microglia (DAM) polarization. However, GWAS revealed that loss‐of‐function mutations of its encoding gene are an important risk factor for AD. There is mounting evidence supporting a biphasic microglial response in AD trajectory, and such contrasting effects would support this. We evaluated the influence of cerebrospinal fluid soluble TREM2 (CSF sTREM2) on AD pathology in healthy, Mild Cognitive Impairment (MCI), and AD patients. Method: Patients were grouped by diagnosis and each group segmented according to amyloid and tau, into amyloid‐positive (Aβ+) and negative (Aβ‐), and tau‐positive (tau+) and negative (tau‐). We used a combination of CSF biomarkers and positron emission tomography (PET) scans to assess neuropathological substrates of AD: CSF p‐tau181 for tau pathology, CSF Amyloid‐β 42 (Aβ42) and 18F‐florbetapir (18F‐AV45) PET scans for amyloid deposition, and magnetic resonance imaging (MRI) scans for neurodegeneration. Result: We observed higher sTREM2 levels in Aβ+/tau+ AD compared with Aβ+/tau‐ AD and Aβ‐/tau‐ MCI patients. Likewise, Aβ+/tau+ MCI patients showed higher sTREM2 than Aβ‐/tau‐MCI patients. Furthermore, sTREM2 levels were negatively associated with cortical volume in MCI and AD, and with MMSE scores in AD. sTREM2 was positively associated with CSF p‐tau181 in all groups except Aβ+ controls. However, a positive association with CSF Aβ42 was only observed in the Aβ‐ control and the Aβ+ and Aβ‐ MCI groups. Similarly, sTREM2 was positively correlated with amyloid load (18F‐AV45 uptake) in controls and MCI patients yet negatively correlated in the AD group. Conclusion: The MCI and AD stages of the disease showed contrasting associations between sTREM2 and neuroimaging markers for AD pathology. These suggest diverging effects of the microglial response along AD trajectory, with a neuroprotective phase in early AD and a neurotoxic one later on. This could indicate that microglia polarize first towards an anti‐inflammatory phenotype before switching to a pro‐inflammatory one as neuropathology progresses. [ABSTRACT FROM AUTHOR]

After learning to categorize a set of alien-like stimuli in the context of a story, a group of 5-year-old children and adults judged pairs of stimuli from different categories to be less similar than did groups not learning the category distinction. In a same-different task, the learning group made more errors on pairs of non-identical stimuli from the same category than did the other groups, suggesting increased within-category item similarity, or compression. These expansion and compression effects add further support to the view that concept formation involves systematic changes in the metric of similarity space within which objects are represented. They also suggest that these processes do not vary with age, which is at least consistent with the hypothesis that they are fundamental to the mechanisms underlying concept formation.

Background: Concurrent alcohol and cannabis (i.e. marijuana) use (CAM; use of both substances within the same specified time frame) is prevalent among college students and associated with increased risk of negative substance-related consequences. Extant research supports the use of protective behavioral strategies (PBS) for reducing negative consequences associated with both alcohol and cannabis use. However, limited research exists regarding the efficacy of PBS among CAM users, and it is unknown whether using PBS for both alcohol and cannabis augments protective effects. The present study tested four moderation models to evaluate the interactive effects of alcohol and cannabis PBS on alcohol and cannabis negative consequences and use frequency. Methods: A multisite sample of college students (N = 1705) reporting past-month CAM use completed questionnaires regarding substance use behaviors, PBS use, and substance-related negative consequences. Results: Alcohol and cannabis PBS were negatively associated with alcohol and cannabis use, respectively. However, two-way interactions between PBS on substance use were not supported, such that negative associations between PBS and same-substance use were not augmented as other-substance PBS use increased. Interactive effects of alcohol and cannabis PBS on negative alcohol and cannabis consequences were supported, such that negative associations between alcohol PBS and consequences were augmented as cannabis PBS increased and vice versa. Conclusions: Findings suggest that using both types of PBS may increase protective effects against negative consequences among CAM users. Accordingly, promoting both types of PBS may enhance extant harm reduction interventions. [ABSTRACT FROM AUTHOR]

Negative affect regulation models suggest that marijuana may be used to reduce negative affect. Extant research has provided support for these models, indicating that specific motives for marijuana use, particularly coping motives (i.e., using to alleviate negative affects), mediate relations between affective vulnerabilities and marijuana outcomes. However, sleep motives (i.e., using to promote sleep) have been neglected from such models, despite their theoretical relevance. The present study tested two multiple mediation models in a large sample of marijuana-using college students (N = 1,453) to evaluate the indirect effects of coping and sleep motives in paths from depressive and anxiety symptoms to marijuana outcomes (use, consequences, and cannabis use disorder [CUD] symptoms). Both coping and sleep motives mediated the effects of depressive/anxiety symptoms on each marijuana variable. Moreover, significant double mediated effects were found, such that higher affective symptoms were associated with greater motives; which were associated with more marijuana use; which was related to more negative consequences and CUD symptoms. The findings provide support for sleep motives as a relevant pathway between affective vulnerabilities and marijuana outcomes. Additional research is needed to evaluate the potential benefits of interventions targeting specific marijuana motives. [ABSTRACT FROM AUTHOR]