Understanding the implications of the biobehavioral basis of nicotine addiction and its impact on the efficacy of treatment

Physiologic Effects of Substance Use

Physiologic and psychological effects of substance use are common occurrences. They may be the proximate purpose of the exposure or related to an unintended complication. Acute short-term exposure effects may not be the same as long-term effects. These effects are mediated by different receptors they act on and the homeostatic changes that occur due to repeat exposure. We review in this article the physiologic and psychological effects from exposure to commonly encountered drugs, ethanol, sedative hypnotics, cocaine, amphetamines, marijuana, opioids, nicotine, hydrocarbons (halogenated and non-halogenated), and nitrous oxide.

Del consumo ocasional del tabaco a la adicción a la nicotina

Introducción. El consumo ocasional de nicotina puede generar una dependencia o adicción, siendo detectable mediante modificaciones en los mecanismos neurobiológicos. Objetivo. Contextualizar del consumo a la adicción e identificar teóricamente el  mecanismo neurobiológico de transición del consumo regular del tabaco a la adicción de la nicotina. Metodología. Se realizó una búsqueda de artículos en inglés y español usando diferentes bases de datos y combinaciones de palabras clave, se seleccionaron los artículos que describieran las características de los procesos neurobiológicos implicados en el uso o consumo intermitentedel tabaco a la adicción a la nicotina como el tema principal. Resultados. El número de investigaciones relacionados a este tema es reducido, aún más en relación con la descripción de los procesos y cambios neurales de la adicción a la nicotina. La adicción a las drogas es un proceso neuroconductual complejo que altera los circuitos del sistema de motivaciónrecompensa del cerebro, por la disminución de la dopamina y la afectación en la regulación del glutamato en los ganglios basales y extensión de la amígdala se asocia con el craving, la anticipación y el déficit en la función ejecutiva. Conclusiones. El tabaco está considerado como una droga legal, por lo que su consumo pareciera ser inofensivo. Sin embargo, las evidencias muestran que su consumo a largo plazo tiene consecuencias graves en la salud de los individuos. El entender cómo cambia el hábito de fumar ocasionalmente al consumocrónico nos hace más conscientes sobre las adaptaciones en el cerebro.

Youth Assets, Neighborhood Factors, Parental Income, and Tobacco Use: A Longitudinal Study of Health Disparities

This study aimed to assess how the relationship between youth assets and future no-tobacco use among youth might differ according to race/ethnicity, neighborhood factors and socio-economic status. Five waves of annual data were collected from 1111 youth/parent pairs living in Oklahoma, USA who were randomly selected to participate in the Youth Asset Study (YAS). A marginal logistic regression model using all five waves of no-tobacco use, demographics, and their interaction was used to compare the change in tobacco use over time. Among 1111 youth, (Mean age = 14.3; 53% female; 39% White, 28% Hispanic, 24% Black, and 9% other), the percentage of youth tobacco use increased significantly from baseline to wave 5 (4 years after baseline) for all racial/ethnic groups and all parental income groups. Assets were prospectively associated with no tobacco use in the past 30 days for Black, White and Hispanic youth and for youth in all income categories (adjusted odds ratio range = 1.9-2.7). There was one statistically significant association between the neighborhood environment and future no tobacco use. To conclude, the protective effects of youth assets in terms of prevention of tobacco use among youth do not differ by youth race/ethnicity or parental income in the presence of neighborhood environmental factors.

Nicotine abolishes memory-related synaptic strengthening and promotes synaptic depression in the neurogenic dentate gyrus of miR-132/212 knockout mice

Micro-RNAs (miRNAs) are highly evolutionarily conserved short-length/noncoding RNA molecules that modulate a wide range of cellular functions in many cell types by regulating the expression of a variety of targeted genes. miRNAs have also recently emerged as key regulators of neuronal genes mediating the effects of psychostimulant drugs and memory-related neuroplasticity processes. Smoking is a predominant addictive behaviour associated with millions of deaths worldwide, and nicotine is a potent natural psychoactive agonist of cholinergic receptors, highly abundant in cigarettes. The influence of miRNAs modulation on cholinergic signalling in the nervous system remains however poorly explored. Using miRNA knockout mice and biochemical, electrophysiological and pharmacological approaches, we examined the effects of miR-132/212 gene disruption on the levels of hippocampal nicotinic acetylcholine receptors, total ERK and phosphorylated ERK (pERK) and MeCP2 protein levels, and studied the impact of nicotine stimulation on hippocampal synaptic transmission and synaptic depression and strengthening. miR-132/212 deletion significantly altered α7-nAChR and pERK protein levels, but not total ERK or MeCP2, and resulted in both exacerbated synaptic depression and virtually abolished memory-related synaptic strengthening upon nicotine stimulation. These observations reveal a functional miRNAs/nicotinergic signalling interplay critical for nicotinic-receptor expression and neuroplasticity in brain structures relevant for drug addiction and learning and memory functions.

Randomized Clinical Trials Investigating Innovative Interventions for Smoking Cessation in the Last Decade

Every year, billions of dollars are spent treating smoking and related conditions, yet smoking-related morbidity and mortality continue to rise. There are currently only three FDA-approved medications for smoking cessation: nicotine replacement therapy, bupropion, and varenicline. Although these medications increase abstinence rates, most individuals relapse following treatment. This chapter reviews clinical trials published within the past 10 years investigating novel smoking cessation pharmacotherapies. Among these pharmacotherapies, some showed promising results, such as cytisine and endocannabinoid modulators, whereas others failed to produce significant effects. More research is needed to develop drugs that produce higher rates of long-term abstinence and to determine which subgroups of patients benefit from a given treatment.

Off-label uses of drugs for depression

The prescription of drugs for depression is rising rapidly. One of the reasons for this trend is their many off-label uses. Up to one third of all prescriptions are for non-indicated use, which in addition to drug repurposing includes different dosing or duration than those recommended. In this review, we elaborate on what antidepressants can treat besides depression. The five classes of drugs for depression are introduced, and their mechanisms of action and serious side effects are described. The most common off-label uses of antidepressants are discussed, with a special focus on treating eating disorders, sleep problems, smoking cessation and managing chronic pain. Depression is often a comorbidity when antidepressants are chosen as therapy, but good therapeutic effects have been observed for other conditions also when depression is not involved. Finally, a new type of antidepressant developed from the hallucinogenic "party drug" ketamine is briefly introduced. This recent development suggests that antidepressants will keep playing a central role in medicine for years to come.