Association of adolescent symptoms of depression and anxiety with daily smoking and nicotine dependence in young adulthood : findings from a 10-year longitudinal study

Aims To examine the association of adolescent depression and anxiety symptoms with daily smoking and nicotine dependence in young adulthood.

Design A prospective cohort study of adolescent and young adult health (n = 1943). Teen assessments occurred at 6-monthly intervals, with two follow-up assessments in young adulthood (wave 7, 1998; wave 8, 2001–03).

Setting Victoria, Australia.

Participants Students who participated at least once during the first six (adolescent) waves of the cohort study.

Measurements Adolescent depression and anxiety symptomswere assessed using the Revised Clinical Interview Schedule (CIS-R).Young adult tobacco usewas defined as: daily use (6 or 7 days perweek) and dependent use (>4 on the Fagerstrom Test for Nicotine Dependence).

Findings Among adolescent ‘less than daily’ smokers, those with high levels of depression and anxiety symptoms had an increased risk of reporting nicotine dependence in young adulthood [odds ratio (OR) 3.3, 95% confidence interval (CI) 1.2–9.1] compared to young adults who had low levels of adolescent depression and anxiety symptoms, after adjusting for potential confounding factors. Similarly, in the adjusted model (OR 1.9, 95% CI 1.0–3.4), among adolescent ‘daily’ smokers, those with high levels of depression and anxiety symptoms had an almost two-fold increase in the odds of reporting nicotine dependence in young adulthood compared to young adults with low levels of adolescent depression and anxiety symptoms.

Conclusions Adolescent smokerswith depression and anxiety symptoms are at increased risk for nicotine dependence into young adulthood. They warrant vigilance from primary care providers in relation to tobacco use well into adulthood.

Nicotine dependence in a prospective population-based study of adolescents : the protective role of a functional tyrosine hydroxylase polymorphism

Dopamine is a key neurotransmitter of the mesolimbic reward pathway in the human brain, and tyrosine hydroxylase (TH) is the rate-limiting enzyme in dopamine biosynthesis. Consequently, the gene encoding TH is a strong candidate for involvement in the genetic component of addiction. The importance of this gene in nicotine dependence is supported by many studies showing a link between nicotine administration and TH expression. A functional tetranucleotide repeat polymorphism within intron 1 of the TH gene (HUMTH01-VNTR) has been shown to modify tobacco use in two independent Caucasian samples from the USA and Australia. Using information drawn from an eight-wave Australian population-based longitudinal study of adolescent health, we tested the effect of the HUMTH01-VNTR on nicotine dependence. Comparisons were made between dependent smokers and non-dependent smokers. These data provide further support for a protective association between the K4 allele and dependent smoking (odds ratio 0.54, 95% confidence interval 0.28-1.0). No associations were observed at any of three other common TH polymorphisms (rs6356, rs6357 and HUMTH01-PstI). Including these data, three independent studies, two of which use identical phenotypes, have now identified a protective relationship between the K4 allele of the functional HUMTH01-VNTR polymorphism and high-level smoking.

Striving for success or addiction? Exercise dependence among elite Australian athletes

Exercise dependence is a condition that involves a preoccupation and involvement with training and exercise, and has serious health and performance consequences for athletes. We examined the validity of a biopsychosocial model to explain the development and maintenance of exercise dependence among elite Australian athletes. Participants were 234 elite Australian athletes recruited from institutes and academies of sport. Thirty-four percent of elite athletes were classified as having exercise dependence based on high scores on the measure of exercise dependence. These athletes had a higher body mass index, and more extreme and maladaptive exercise beliefs compared to non-dependent athletes. They also reported higher pressure from coaches and teammates, and lower social support, compared to athletes who were not exercise dependent. These results support the utility of a biopsychosocial model of exercise dependence in understanding the aetiology of exercise dependence among elite athletes. Limitations of the study and future research directions are highlighted.

Oxygen dependence of metabolism and cellular adaptation in vertebrate muscles: a review

The key roles the cardiovascular system play in the complex distribution of blood, and consequently oxygen, have been extensively studied in vertebrates. Numerous studies have also revealed the complex and varied ways in which tissues cope with compromised oxygen supply. The links between these two processes are the subject of much current research. This article aims to review how blood supply influences tissue oxygenation and affects metabolism, and how this might have played a role in the evolution of the complex muscle arrangements which characterise vertebrates. Muscle tissue is the greatest proportion of body mass in most vertebrates and undergoes dramatic alterations in metabolism and associated oxygen flux. Special attention is given to the myotome of fishes, in which the partitioning of the fibre types contrasts with the mosaic arrangement of tetrapods. This gives us the opportunity to study pure whole vascularised muscle blocks, rather than single fibres, and further explore the interrelationship between oxygen supply and tissue energetics.

Oxygen-dependence of metabolic rate in the muscles of craniates

We present evidence that oxygen consumption (V_O2 ) is oxygen partial pressure (P_O2) dependent in striated muscles and P_O2 -independent in the vasculature in representatives of three craniate taxa: two teleost fish, a hagfish and a rat. Blood vessel V_O2 displayed varying degrees of independence in a P_O2 range of 15–95 mmHg, while V_O2 by striated muscle tissue slices from all species related linearly to P_O2 between 0 and 125 mmHg, despite V_O2 rates varying greatly between species and muscle type. In salmon red muscle, lactate concentrations fell in slices incubated at a P_O2 of either 30 or 100 mmHg, suggesting aerobic rather than anaerobic metabolism. Consistent with this finding, potential energy, a proxy of ATP turnover, was P_O2 -dependent. Our data suggest that the reduction in V_O2 with falling P_O2 results in a decrease in ATP demand, suggesting that the hypoxic signal is sensed and cellular changes effected. Viability and diffusion limitation of the preparations were investigated using salmon cardiac and skeletal muscles. Following the initial P_O2 depletion, reoxygenation of the Ringer bathing salmon cardiac muscle resulted in V_O2^s that was unchanged from the first run. V_O2 increased in all muscles uncoupled with p-trifluoromethoxylphenyl-hydrazone (FCCP) and 2,4-dinitrophenol (DNP). Mitochondrial succinate dehydrogenase activity, quantified by reduction of 3-(4,5-dimethylthiazol)-2,5-diphenyl-2H-tetrazolium bromide (MTT) to formazan, was constant over the course of the experiment. These three findings indicate that the tissues remained viable over time and ruled out diffusion-limitation as a constraint on V_O2.

Cigarette smoking, nicotine dependence and anxiety disorders : a systematic review of population-based, epidemiological studies

Background Multiple studies have demonstrated that rates of smoking and nicotine dependence are increased in individuals with anxiety disorders. However, significant variability exists in the epidemiological literature exploring this relationship, including study design (cross-sectional versus prospective), the population assessed (random sample versus clinical population) and diagnostic instrument utilized.

Methods We undertook a systematic review of population-based observational studies that utilized recognized structured clinical diagnostic criteria (Diagnostic and Statistical Manual of Mental Disorders (DSM) or International Classification of Diseases (ICD)) for anxiety disorder diagnosis to investigate the relationship between cigarette smoking, nicotine dependence and anxiety disorders.

Results In total, 47 studies met the predefined inclusion criteria, with 12 studies providing prospective information and 5 studies providing quasiprospective information. The available evidence suggests that some baseline anxiety disorders are a risk factor for initiation of smoking and nicotine dependence, although the evidence is heterogeneous and many studies did not control for the effect of comorbid substance use disorders. The identified evidence however appeared to more consistently support cigarette smoking and nicotine dependence as being a risk factor for development of some anxiety disorders (for example, panic disorder, generalized anxiety disorder), although these findings were not replicated in all studies. A number of inconsistencies in the literature were identified.

Conclusions Although many studies have demonstrated increased rates of smoking and nicotine dependence in individuals with anxiety disorders, there is a limited and heterogeneous literature that has prospectively examined this relationship in population studies using validated diagnostic criteria. The most consistent evidence supports smoking and nicotine dependence as increasing the risk of panic disorder and generalized anxiety disorder. The literature assessing anxiety disorders increasing smoking and nicotine dependence is inconsistent. Potential issues with the current literature are discussed and directions for future research are suggested.

Mutually assured destruction or co-dependence? The G20 and the UN

The G20 forum has acted to crystallise important changes in the architecture of global governance emerging since the 1970s. This has seen the locus of power shift away from the United Nations (UN) System as smaller and poorer states become increasingly adept at exercising their power within UN structures. Yet it is too simple to set the G20 against the UN, for example as minilateralism versus multilateralism. While the UN seems increasingly constrained and less relevant, it is not about to disappear. Moreover, we argue there are two significant obstacles to the G20 claiming the mantle of dominant global governance institution. First, that minilateralism is still a form of multilateralism, and ultimately subject to the same problems with the generation of consensus if extended, as in the G20, to include sufficiently diverse state members for a claim of legitimacy. Second, its emergence from the Global Financial Crisis and historical focus on financial governance means its agenda is excessively narrow at a time when food and environmental crises command similar global political significance. We conclude by considering some of the different elements of the emerging G20/UN dynamic, and whether this emerging dialectic can enhance prospects for wide ranging reforms to global trade, finance and economic structures that are currently incapable of functioning sustainably or preventing wide scale famine.

MAKINGtheLINK : a school-based health promotion programme to increase help-seeking for cannabis and mental health issues among adolescents

Aim: There is increasing concern regarding the use of cannabis among adolescents, especially given recent evidence highlighting its link with later mental disorders. Encouraging young people with mental health or drug issues to seek professional help is an important early intervention strategy; however, adolescents are typically reluctant to do so and instead turn to their peers for help. Peers may not have the skills or knowledge required to assist their friends to access professional help. This paper describes the development and evaluation of MAKINGtheLINK, a school-based health promotion programme that promotes help-seeking behaviour for mental health and cannabis use issues among young people.

Methods: The MAKINGtheLINK programme was piloted with 182 Year 10 students at a secondary school in Melbourne, Australia. Forty teachers received the MAKINGtheLINK staff professional development session.

Results: The delivery of the MAKINGtheLINK programme was found to be both acceptable and feasible within a school setting. Students and teachers described it as a fun, engaging, helpful and important programme. Students reported increased confidence and awareness of how to seek help for themselves or a friend, and teachers indicated increased confidence and awareness of how to assist students to seek help for cannabis use and/or mental health problems.

Conclusions: MAKINGtheLINK was successfully implemented within the school curriculum. We believe this is the first school-based programme that specifically focuses on facilitating professional help-seeking for cannabis use and mental health problems among young people, and demonstrates that utilizing peer models for help-seeking is a valuable resource for early intervention initiatives.