Cannabis abuse as a risk factor for depressive symptoms
ABSTRACT This study sought to estimate the degree to which cannabis abuse is a risk factor for depressive symptoms rather than an effort to self-medicate depression.
Participants (N=1,920) in the 1980 Baltimore Epidemiologic Catchment Area (ECA) study who were reassessed between 1994 and 1996 as part of a follow-up study provided the data. The analysis focused on two cohorts: those who reported no depressive symptoms at baseline (N=849) and those with no diagnosis of cannabis abuse at baseline (N=1,837). Symptoms of depression, cannabis abuse, and other psychiatric disorders were assessed with the Diagnostic Interview Schedule.
In participants with no baseline depressive symptoms, those with a diagnosis of cannabis abuse at baseline were four times more likely than those with no cannabis abuse diagnosis to have depressive symptoms at the follow-up assessment, after adjusting for age, gender, antisocial symptoms, and other baseline covariates. In particular, these participants were more likely to have experienced suicidal ideation and anhedonia during the follow-up period. Among the participants who had no diagnosis of cannabis abuse at baseline, depressive symptoms at baseline failed to significantly predict cannabis abuse at the follow-up assessment.
Further research is needed to identify characteristics of individuals who abuse cannabis that account for their higher risk of depression to estimate the degree of impairment resulting from their depression.
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ABSTRACT: El cannabis es una de las drogas de abuso más frecuentes. Afecta al sistema de recompensa cerebral en los animales, y tiene un potencial de recompensa y adicción demostrado en el ser humano. Hemos utilizado la RM funcional para medir la actividad cerebral durante la anticipación de la recompensa en una tarea de recompensa monetaria. Se comparó a consumidores crónicos de cannabis con individuos de control sanos. Se utilizó otro grupo control adicional formado por consumidores de nicotina. Los consumidores de cannabis mostraron una actividad cerebral atenuada durante la anticipación de la recompensa en el núcleo accumbens, en comparación con los controles no fumadores, pero no en comparación con los controles fumadores. Los consumidores de cannabis mostraron una reducción de la actividad de anticipación de recompensa en el núcleo caudado, en comparación con los controles tanto fumadores como no fumadores. Estos datos sugieren que la nicotina puede ser responsable de una atenuación de la actividad de anticipación de recompensa en el núcleo accumbens, pero que las diferencias que se producen en el caudado se asocian al consumo de cannabis. Nuestros resultados implican que el consumo crónico de cannabis, así como el de nicotina, puede causar una alteración de la respuesta cerebral a los estímulos de recompensa.04/2011; 18(2):45-54. DOI:10.1016/j.psiq.2011.08.003
Journal of psychiatry & neuroscience: JPN 09/2014; 39(5):339-47. · 7.49 Impact Factor
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ABSTRACT: Background Whole school, ethos-changing interventions reduce risk behaviours in middle adolescence, more than curriculum-based approaches. Effects on older ages are not known. We set out to replicate one of these interventions, Australia’s Gatehouse Project, in a rural Canadian high school. Methods A guided, whole school change process sought to make students feel more safe, connected, and valued by: changes in teaching practices, orientation processes, professional development of staff, recognition and reward mechanisms, elevating student voice, and strategies to involve greater proactivity and participation. We conducted risk behaviour surveys in grades 10 to 12 before the intervention and 2 years afterwards, and social network analyses with the staff. Changes in health and health risk behaviours were assessed using chi-square. Interactions between the intervention and gender and between the intervention and school engagement were assessed using interaction terms in logistic regression models. Changes in the density of relationships among staff were tested with methods analogous to paired t-tests. Results Like Gatehouse, there was no statistically significant reduction in depressive symptoms or bullying, though the trend was in that direction. Among girls, there was a statistically significant decrease in low school engagement (45% relative reduction), and decreases in drinking (46% relative reduction), unprotected sex (61% relative reduction) and poor health (relative reduction of 73%). The reduction in drinking matched the national trend. Reductions in unprotected sex and poor health went against the national trend. We found no statistically significant changes for boys. The effects coincided with statistically significant increases in the densities of staff networks, indicating that part of the mechanism may be through relationships at school. Conclusions A non-specific, risk protective intervention in the social environment of the school had a significant impact on a cluster of risk behaviours for girls. Results were remarkably like reports from similar school environment interventions elsewhere, albeit with different behaviours being affected. It may be that this type of intervention activates change processes that interact highly with context, impacting different risks differently, according to the prevalence, salience and distribution of the risk and the interconnectivity of relationships between staff and students. This requires further exploration.BMC Public Health 03/2015; 15:265. DOI:10.1186/s12889-015-1538-3 · 2.32 Impact Factor