Motivation Matters: Understanding the Antidepressant Mechanism of Physical Activity among Young Adults

International Journal of Exercise Science 17(5): 861-873, 2024. A negative association between physical activity and depressive symptoms is consistently reported within scientific literature and physical self-concept has been suggested to mediate this pathway. However, for whom these associations are strongest remains poorly understood, and little is known about how other psychosocial factors might be implicated. Consequently, we examined how various exercise motivations, specifically appearance, physical health, and mental health, might moderate the indirect effect of physical activity on depressive symptoms through physical self-concept. Canadian young adults (N = 496, Mage = 20.36, SD = 1.87) completed an online questionnaire. Mediation and moderated-mediation models were tested using PROCESS macro in RStudio. A significant indirect effect (ß = -0.18, CI [-0.005, -0.003]) of physical activity on depressive symptoms through physical self-concept was found. Exercise motivations moderated the association between physical activity and physical self-concept, such that the association was stronger when individuals were motivated by physical health. Thus, the effect of physical activity on depressive symptoms varied according to physical self-concept and physical health-exercise motivations. We conclude that motivation should be considered when developing and delivering physical activity prevention efforts for depressive symptoms

Brief report: how adolescents with ASD process social information in complex scenes. Combining evidence from eye movements and verbal descriptions

We investigated attention, encoding and processing of social aspects of complex photographic scenes. Twenty-four high-functioning adolescents (aged 11–16) with ASD and 24 typically developing matched control participants viewed and then described a series of scenes, each containing a person. Analyses of eye movements and verbal descriptions provided converging evidence that both groups displayed general interest in the person in each scene but the salience of the person was reduced for the ASD participants. Nevertheless, the verbal descriptions revealed that participants with ASD frequently processed the observed person’s emotion or mental state without prompting. They also often mentioned eye-gaze direction, and there was evidence from eye movements and verbal descriptions that gaze was followed accurately. The combination of evidence from eye movements and verbal descriptions provides a rich insight into the way stimuli are processed overall. The merits of using these methods within the same paradigm are discussed

Cassiosomes are stinging-cell structures in the mucus of the upside-down jellyfish Cassiopea xamachana

This work is licensed under a Creative Commons Attribution 4.0 International License.Snorkelers in mangrove forest waters inhabited by the upside-down jellyfish Cassiopea xamachana report discomfort due to a sensation known as stinging water, the cause of which is unknown. Using a combination of histology, microscopy, microfluidics, videography, molecular biology, and mass spectrometry-based proteomics, we describe C. xamachana stinging-cell structures that we term cassiosomes. These structures are released within C. xamachana mucus and are capable of killing prey. Cassiosomes consist of an outer epithelial layer mainly composed of nematocytes surrounding a core filled by endosymbiotic dinoflagellates hosted within amoebocytes and presumptive mesoglea. Furthermore, we report cassiosome structures in four additional jellyfish species in the same taxonomic group as C. xamachana (Class Scyphozoa; Order Rhizostomeae), categorized as either motile (ciliated) or nonmotile types. This inaugural study provides a qualitative assessment of the stinging contents of C. xamachana mucus and implicates mucus containing cassiosomes and free intact nematocytes as the cause of stinging water

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Reciprocal Effects of Internalizing and Oppositional Defiance Symptoms on Heavy Drinking and Alcohol-Related Harms in Young Adulthood

There is a need for longitudinal research to understand how psychopathology relates to the onset and maintenance of substance use from adolescence into young adulthood. Hence, we investigate the longitudinal, reciprocal influences of internalizing (anxiety and depression) and externalizing (oppositional defiance) symptoms on heavy episodic drinking (HED; ≥5 drinks per occasion) and alcohol-related harms in a community-based sample of youth aged 12–27 years. Participants were chosen from the Victoria Healthy Youth Survey, followed six times, biennially between 2003 and 2013 ( N = 662). Analyses used cross-lagged panel models to examine reciprocal relations over time. Differences across age and sex were also tested. Defiance symptoms predicted increases in HED, which reciprocally predicted increases in defiance symptoms for females. Internalizing symptoms were related to HED within time for females. Alcohol-related harms had reciprocal positive associations with internalizing and defiance symptoms for both males and females. Associations were largely invariant across age groups, suggesting that the presence and strength of associations persisted across development. While psychopathology preceded the onset of HED and harms, the overall findings suggest that these risk processes are mutually reinforcing across development and that youth may become entrenched in an interdependent cycle that significantly increases their risk of comorbid disorders in adulthood

Age-varying effects of cannabis use frequency and disorder on symptoms of psychosis, depression and anxiety in adolescents and adults.

AIMS: We tested the age-varying associations of cannabis use (CU) frequency and disorder (CUD) with psychotic, depressive and anxiety symptoms in adolescent and adult samples. Moderating effects of early onset (≤ 15 years) and sex were tested. DESIGN: Time-varying effect models were used to assess the significance of concurrent associations between CU and CUD and symptoms of psychosis, depression and anxiety at each age. SETTING AND PARTICIPANTS: Adolescent data (V-HYS; n = 662) were collected from a randomly recruited sample of adolescents in Victoria, British Columbia, Canada during a 10-year period (2003-13). Adult cross-sectional data (NESARC-III; n = 36 309) were collected from a representative sample from the United States (2012-13). MEASUREMENTS: Mental health symptoms were assessed using self-report measures of diagnostic symptoms. CU was based on frequency of past-year use. Past-year CUD was based on DSM-5 criteria. FINDINGS: For youth in the V-HYS, CU was associated with psychotic symptoms following age 22 [b = 0.13, 95% confidence interval (CI) = 0.002, 0.25], with depressive symptoms from ages 16-19 and following age 25 (b = 0.17, 95% CI = 0.003, 0.34), but not with anxiety symptoms. CUD was associated with psychotic symptoms following age 23 (b = 0.51, 95% CI = 0.01, 1.01), depressive symptoms at ages 19-20 and following age 25 (b = 0.71, 95% CI = 0.001, 1.42) and anxiety symptoms ages 26-27 only. For adults in the NESARC-III, CU was associated with mental health symptoms at most ages [e.g. psychotic symptoms; age 18 (b = 0.22, 95% CI = 0.10, 0.33) to age 65 (b = 0.36, 95% CI = 0.16, 0.56)]. CUD was associated with all mental health symptoms across most ages [e.g. depressive symptoms; age 18 (b = 0.96, 95% CI = 0.19, 1.73) to age 61 (b = 1.11, 95% CI = 0.01, 2.21)]. Interactions with sex show stronger associations for females than males in young adulthood [e.g. V-HYS: CUD × sex interaction on psychotic symptoms significant after age 26 (b = 1.12, 95% CI = 0.02, 2.21)]. Findings were not moderated by early-onset CU. CONCLUSIONS: Significant associations between cannabis use (CU) frequency and disorder (CUD) and psychotic and depressive symptoms in late adolescence and young adulthood extend across adulthood, and include anxiety

Frequent marijuana use and driving risk behaviours in Canadian youth

Background: A better understanding of the relations between patterns of marijuana use and driving risks in young adulthood is needed. Methods: Secondary analyses of self-report data from the Victoria Healthy Youth Survey. Youth (baseline ages 12 to 18; N=662; 52% females) were interviewed biannually (on six occasions) from 2003 to 2013 and classified as abstainers (i.e., used no marijuana in past 12 months), occasional users (i.e., used at most once per week), and frequent users (i.e., used more than once a week). Results: In the frequent user group, 80% of males and 75% of females reported ‘being in a car driven by driver (including themselves) using marijuana or other drugs in the last 30 days’, 64% of males and 33% of females reported that they were ‘intoxicated’ with marijuana while operating a vehicle and 50% of males and 42% of females reported being in a car driven by a driver using alcohol. In addition, 28% of occasional users and also a small proportion of abstainers reported ‘being in a car driven by a driver using marijuana or other drugs in the last 30 days’. Interpretation: The high frequency of driving risk behaviours, particularly for frequent users, suggest that plans for legalization of recreational use should anticipate the costs of preventive education efforts that present an accurate picture of potential risks for driving. Youth also need to understand risks for dependence, and screening for and treatment of marijuana use disorders is needed.Medicine, Faculty ofNon UBCEmergency Medicine, Department ofReviewedFacultyOthe

Supplemental Material - Adherence to and Motivations for Complying With Public Health Measures Among Adolescents During the Coronavirus Disease (COVID-19) Pandemic in Canada

Supplemental Material for Adherence to and Motivations for Complying With Public Health Measures Among Adolescents During the Coronavirus Disease (COVID-19) Pandemic in Canada by Stephanie G. Craig, Christina L. Robillard, Megan E. Ames, Samantha Feldman and Debra J. Pepler in Psychological Reports</p