IMPORTANCE Increases in screen time have been found to be associated with increases in depressive symptoms. However, longitudinal studies are lacking. OBJECTIVE To repeatedly measure the association between screen time and depression to test 3 explanatory hypotheses: displacement, upward social comparison, and reinforcing spirals. DESIGN, SETTING, AND PARTICIPANTS This secondary analysis used data from a randomized clinical trial assessing the 4-year efficacy of a personality-targeted drug and alcohol prevention intervention. This study assessed screen time and depression throughout 4 years, using an annual survey in a sample of adolescents who entered the seventh grade in 31 schools in the Greater Montreal area. Data were collected from September 2012 to September 2018. Analysis began and ended in December 2018. MAIN OUTCOMES AND MEASURES Independent variables were social media, television, video gaming, and computer use. Symptoms of depression was the outcome, measured using the Brief Symptoms Inventory. Exercise and self-esteem were assessed to test displacement and upward social comparison hypothesis. RESULTS A total of 3826 adolescents (1798 girls [47%]; mean [SD] age, 12.7 [0.5] years) were included. In general, depression symptoms increased yearly (year 1 mean [SD], 4.29 [5.10] points; year 4 mean [SD], 5.45 [5.93] points). Multilevel models, which included random intercepts at the school and individual level estimated between-person and within-person associations between screen time and depression. Significant between-person associations showed that for every increased hour spent using social media, adolescents showed a 0.64-unit increase in depressive symptoms (95% CI, 0.32-0.51). Similar between-level associations were reported for computer use (0.69; 95% CI, 0.47-0.91). Significant within-person associations revealed that a further 1-hour increase in social media use in a given year was associated with a further 0.41-unit increase in depressive symptoms in that same year. A similar within-person association was found for television (0.18; 95% CI, 0.09-0.27). Significant between-person and within-person associations between screen time and exercise and self-esteem supported upward social comparison and not displacement hypothesis. Furthermore, a significant interaction between the between-person and within-person associations concerning social media and self-esteem supported reinforcing spirals hypothesis. CONCLUSIONS AND RELEVANCE Time-varying associations between social media, television, and depression were found, which appeared to be more explained by upward social comparison and reinforcing spirals hypotheses than by the displacement hypothesis. Both screen time modes should be taken into account when developing preventive measures and when advising parents.

For over a century, research on psychopathology has focused on categorical diagnoses. Although this work has produced major discoveries, growing evidence points to the superiority of a dimensional approach to the science of mental illness. Here we outline one such dimensional system-the Hierarchical Taxonomy of Psychopathology (HiTOP)-that is based on empirical patterns of psychological symptom co-occurrence. We highlight key ways in which this framework can advance mental health research, and we provide some heuristics for using HiTOP to test theories of psychopathology. We then review emerging evidence that supports the value of a hierarchical, dimensional model of mental illness across diverse research areas in psychological science. These new data suggest that the HiTOP system has the potential to accelerate and improve research on mental health problems as well as efforts to more effectively assess, prevent, and treat mental illness.

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High-quality social connection with friends and family members is associated with reduced likelihood of the past year depression. Intervention studies that target the quality of social support for depression, particularly support from friends, are warranted.

Alcohol and cannabis misuse are related to impaired cognition. When inferring causality, four nonexclusive theoretical models can account for this association: 1) a common underlying vulnerability model; 2) a neuroplasticity model in which impairment is concurrent with changes in substance use but temporary because of neuroplastic brain processes that restore function; 3) a neurotoxicity model of long-term impairment consequential to substance use; and 4) a developmental sensitivity hypothesis of age-specific effects. Using a developmentally sensitive design, the authors investigated relationships between year-to-year changes in substance use and cognitive development. Method: A population-based sample of 3,826 seventhgrade students from 31 schools consisting of 5% of all students entering high school in 2012 and 2013 in the Greater Montreal region were assessed annually for 4 years on alcohol and cannabis use, recall memory, perceptual reasoning, inhibition, and working memory, using school-based computerized assessments. Multilevel regression models, performed separately for each substance, were used to simultaneously test vulnerability (between-subject) and concurrent and lagged within-subject effects on each cognitive domain.

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Identification of both central symptoms, because of their key role in the constellation and strong associations with majority of symptoms, and bridge symptoms, because of their mediating role between two disorders, has some implications in terms of self-medication and risk-taking/self-regulation theories of comorbidity and provides a number of clinical implications, which warrants further exploration within clinical samples.

BackgroundCytotoxic effects of some of the members of papaveraceae family have been reported in Iranian folk medicine. Recent reports has indicated that alkaloids fraction of opium may be responsible for its cytotoxic effect; however, the mechanism of this effect is not fully understood. This study has been designed to investigate the selective cytotoxic, genotoxic and also apoptosis induction effects of noscapine, papaverine and narceine, three non-addictable opium alkaloids, on HT29, T47D and HT1080 cancer cell lines. Mouse NIH3T3 cell line was chosen to present non-cancerous cells and Doxorubicin was selected as the positive control.MethodsCells were treated by different concentrations of Noscapine, Papaverine, Narceine and doxorubicin; viability was assessed by MTT assay. The genotoxicity and apoptosis induction were tested with comet assay and Annexin-V affinity when the concentration of each these drugs is less than its IC50. In addition, the DNA damage and caspase activity of the T47D cells were examined and the results were compared.ResultsThis study noted the cytotoxicity and genotoxicity of noscapine and papaverine, specifically on cancerous cell lines. Furthermore, papaverine induces apoptosis in all studied cancer cell lines and noscapine showed this effect in T47D and HT29 cells but not in NIH-3 T3 cells as noncancerous cell line. narceine also showed genototoxicity in the studied cell lines at its IC50 concentration.ConclusionsThis experiment suggests that noscapine and papaverine may be of use in cancer treatment due to their specific cytotoxicity and genotoxicity. However, further in vivo studies are needed to confirm its usefulness in cancer treatment.