Gareth Richards

Caffeine consumption and self-assessed stress, anxiety and depression in secondary school children

Previous research suggests that effects of caffeine on behaviour are positive unless one is investigating sensitive groups or ingestion of large amounts. Children are a potentially sensitive subgroup, and especially so considering the high levels of caffeine currently found in energy drinks. The present study used data from the Cornish Academies Project to investigate associations between caffeine (both its total consumption, and that derived separately from energy drinks, cola, tea, and coffee) and single-item measures of stress, anxiety, and depression, in a large cohort of secondary school children from the South West of England. After adjusting for additional dietary, demographic, and lifestyle covariates, positive associations between total weekly caffeine intake and anxiety and depression remained significant, and the effects differed between males and females. Initially, effects were also observed in relation to caffeine consumed specifically from coffee. However, coffee was found to be the major contributor to high overall caffeine intake, providing explanation as to why effects relating to this source were also apparent. Findings from the current study increase our knowledge regarding associations between caffeine intake and stress, anxiety, and depression in secondary school children, though the cross-sectional nature of the research made it impossible to infer causality.

A review of energy drinks and mental health, with a focus on stress, anxiety, and depression

Background: Concerns have been expressed regarding the potential for caffeinated energy drinks to negatively affect mental health, and particularly so in young consumers at whom they are often targeted. The products are frequently marketed with declarations of increasing mental and physical energy, providing a short-term boost to mood and performance. Although a certain amount of evidence has accumulated to substantiate some of these claims, the chronic effects of energy drinks on mental health also need to be addressed. Methods: To review the relevant literature, PubMed and PsycINFO were searched for all peer-reviewed articles published in English that addressed associations between energy drink use and mental health outcomes. Case reports were also considered, though empirical studies investigating acute mood effects were excluded as a review of such articles had recently been published. Fifty-six articles were retrieved: 20 of these (along with eight more identified through other means) were included in the current review, and, because the majority addressed aspects of stress, anxiety, and depression, particular focus was placed on these outcomes. Results: Though a number of null findings (and one negative relationship) were observed, the majority of studies examined reported positive associations between energy drink consumption and symptoms of mental health problems. Conclusions: Though the findings imply that energy drink use may increase the risk of undesirable mental health outcomes, the majority of research examined utilized cross-sectional designs. In most cases, it was therefore not possible to determine causation or direction of effect. For this reason, longitudinal and intervention studies are required to increase our understanding of the nature of the relationships observed.

Breakfast and Energy Drink Consumption in Secondary School Children: Breakfast Omission, in Isolation or in Combination with Frequent Energy Drink Use, is Associated with Stress, Anxiety, and Depression Cross-Sectionally, but not at 6-Month Follow-Up

A considerable amount of research suggests that breakfast omission and the frequent use of caffeinated energy drinks may be associated with undesirable effects, and particularly so in children and adolescents. The current paper presents cross-sectional and longitudinal data from the Cornish Academies Project to investigate the effects of consuming energy drinks and missing breakfast on stress, anxiety, and depression in a cohort of secondary school children from the South West of England. Questionnaires were administered at two time-points (spaced 6 months apart) to collect information relating to diet and lifestyle over the previous 6 months. Demographic and school data were acquired through the School Information Management System, and single-item measures of stress, anxiety, and depression were administered at the second time-point only. Associations between breakfast and energy drink consumption and stress, anxiety, and depression were investigated, and a multivariate approach was taken so that additional variance from diet, demography, and lifestyle could be controlled for statistically. Cross-sectional analyses showed that breakfast omission was consistently associated with negative outcomes, and that this was largely observed for both those who frequently consumed energy drinks and those who did not. However, cross-lag analyses showed that neither breakfast omission or energy drink consumption, alone or in combination, was predictive of stress, anxiety, or depression at 6-month follow-up. This suggests that associations between breakfast and mental health may be bi-directional rather than breakfast being the causal factor.

What is the evidence for a link between digit ratio (2D:4D) and direct measures of prenatal sex hormones?

Since Manning et al.s [1] seminal paper was published in 1998, the ratio of length between the second (index) and fourth (ring) fingers (digit ratio, or 2D:4D) has been commonly employed by researchers as an indicator of prenatal sex hormone exposure. However, although an extensive literature now exists on how 2D:4D relates to a range of phenotypic outcomes, to the best of my knowledge there are currently only six papers that examine 2D:4D in relation to direct measures of prenatal sex hormones. Furthermore, the hormones reported on in four of these papers were measured from umbilical cord blood sampled shortly after birth. Although the blood might relate to foetal circulation in late gestation, the hormone levels measured technically relate to the perinatal rather than prenatal period (for a comparison of methods for measuring foetal sex hormones, see van de Beek et al. [2]).

Risk Factors for , and Effects of , Stress , Anxiety , and Depression in Adolescents

Aims: Stress, anxiety, and depression are alarmingly common in the general population, can be extremely debilitating, and are a huge cost to public health services. Understanding risk factors associated with such conditions may therefore be useful in helping devise intervention strategies. Though much research has been conducted in the adult population, relatively few studies have investigated these problems in adolescents from the UK. This is a gap in the literature that the current paper aims to address. Study Design: The current research utilised a cross-sectional design. Place and Duration of Study: Data were collected from three secondary schools in Cornwall, UK, in June 2013. Methodology: Data from the Cornish Academies Project were used to investigate links between demographic and lifestyle variables and single item measures of stress, anxiety, and depression. The sample included 2307 secondary school children aged 11-17 (48.5% male, 51.5% female) from the South West of England. Results: A number of risk factors were identified, including female gender, low sleep hours, and belonging to a higher school year. In addition to this, the effects of stress anxiety, and depression on school attendance, Key Stage 3/Key Stage 4 English and maths attainment, and the occurrence of behavioural sanctions were investigated. After demographic and lifestyle covariates had been controlled for, high stress was found to predict the occurrence of behavioural sanctions, and high depression was associated with below average English and maths attainment. Conclusion: Though the findings presented are informative in themselves, the identification of correlates of mental health problems in this demographic group may also be of benefit to future studies that utilise multivariate approaches to data analysis.

Digit ratio (2D:4D) and circulating testosterone, oestradiol, and progesterone levels across the menstrual cycle

BACKGROUND Digit ratio (2D:4D) is used by researchers as an indicator of prenatal sex hormone exposure. Two previous studies have examined associations between 2D:4D and circulating sex steroid concentrations across the menstrual cycle in adult females. One reported that digit ratio correlated positively with oestradiol levels, whereas the other found no such effect; neither observed significant associations with progesterone. AIMS To examine associations between 2D:4D, as well as asymmetry (i.e. right minus left 2D:4D), and circulating sex steroids across the menstrual cycle. STUDY DESIGN Correlational. SUBJECTS 32 naturally cycling adult females from rural southern Poland. OUTCOME MEASURES Salivary oestradiol, progesterone, testosterone, and testosterone to oestradiol ratio (T:O) measured during the follicular, peri-ovulatory, and luteal phases. Average levels across the cycle were also examined. RESULTS AND CONCLUSIONS Asymmetry in digit ratio correlated positively with oestradiol at each phase, as well as with average levels across the cycle. Each association, other than that relating to average levels, remained statistically significant after a range of covariates had been controlled for. No other significant correlations were observed between digit ratio variables and circulating hormone levels. Our results might suggest that low exposure to androgens and/or high exposure to oestrogens during gestation is a predictor of high oestradiol levels in naturally cycling females of reproductive age. However, considering that it was asymmetry in digit ratio, and not either right or left 2D:4D, that was a significant predictor, it is also possible that these effects reflect more general associations between bilateral asymmetry and circulating oestradiol levels.

Caffeine Consumption and General Health in Secondary School Children: A Cross-sectional and Longitudinal Analysis

Although caffeine is sometimes associated with beneficial effects in adults, the substance may be dangerous if intake is too high. This concern is particularly relevant in regards to children and adolescents, as consumption of energy drinks may be particularly high in such populations. For this reason, the current study examined data from the Cornish Academies Project to determine whether caffeine intake in secondary school children was related to responses to a single-item measure of general health. Two cross-sections of data were available: questionnaires were completed by 2030 at baseline, by 2307 at 6-month follow-up, and by 1660 at both time-points. Relationships were, therefore, explored both cross-sectionally and longitudinally. High caffeine consumption (i.e., 1000 mg/week) was associated with low general health in both cross-sections of data, and analyses of individual caffeine sources suggested that the effects related specifically to cola and energy drinks. However, after controlling for additional aspects of diet, demography, and lifestyle, total weekly intake only remained significantly associated with general health at the latter time-point. Further to this, null findings from cross-lag and change-score analyses suggest that caffeine and general health were unlikely to be causally linked in this sample. However, due to methodological limitations, such as the two cross-sections of data being collected only 6 months apart, it is suggested that further longitudinal and intervention studies are required in order for firm conclusions to be drawn.

Energy drinks, caffeine, junk food, breakfast, depression and academic attainment of secondary school students:

Background: Energy drinks are widely consumed, and concerns have been raised about possible negative outcomes. Aims: The aim of the present research was to examine associations between consumption of energy drinks, caffeine and junk food, and academic attainment in a sample of UK secondary school students. Methods: A total of 3071 students agreed to participate in the study; 2677 completed the survey on one occasion (52.4% female, 47.6% male; approximately 20% of the sample from each school year) and 1660 (49.6% female, 50.4% male) completed the survey a second time, approximately six months later. The academic attainment measure was based on Key Stage 3 and Key Stage 4 grades for Maths and English. Results: In the cross-sectional analyses, logistic regressions showed that consumption of energy drinks was associated with a greater likelihood of being in the low academic achievement group. This was not found for other sources of caffeine. The effect of energy drinks was still significant when demographic, academic and health/lifestyle variables were covaried. However, inclusion of an unhealthy diet variable (junk food) removed the significant effect of energy drinks. Similar observations were made in the longitudinal study, with the poorer attainment of those who consumed energy drinks reflecting breakfast omission and depression. Discussion: The present findings indicate that consumption of energy drinks is associated with an increased likelihood of poor academic attainment that reflects energy drink consumption being part of an unhealthy diet or being associated with skipping breakfast rather than a more specific effect, such as being a source of caffeine. Although the current study extends previous research by utilising a longitudinal design, intervention studies are now required to better answer questions relating to causality and direction of effect.

2D:4D digit ratio and religiosity in university student and general population samples

The ratio of index to ring finger length (2D:4D) is used as a proxy for prenatal sex hormone exposure. It has been hypothesised to correlate with religiosity, though no published research has explored this possibility. Here, we initially examined 2D:4D in relation to self-reported religious affiliation and questionnaire measures of general religiosity, spirituality, religious fundamentalism, and religious commitment in male (N = 106) and female (N = 105) university students (Study 1). Although no significant correlations were observed between 2D:4D and the questionnaire measures, females who affiliated with organised religions had higher digit ratios compared to agnostic or atheist females. Study 2 attempted to replicate these findings in an adult general population sample (N = 172 males, N = 257 females), but did not observe significant effects in either sex. Overall, these findings suggest that high 2D:4D may be relatively-specifically associated with religious affiliation in young, highly-educated, females.

Demographic and lifestyle correlates of school attendance, English and Maths attainment, and the occurrence of behavioural sanctions in British secondary school children

Aims: Performance in school is known to predict a number of important outcomes in later life (e.g. socioeconomic status). For this reason it is considered useful to identify aspects of demography and lifestyle that are associated with low school attendance, low academic attainment, and high occurrences of problem behaviour. Study Design: The current study utilised a cross-sectional design; analyses were performed twice due to the availability of two cross-sections of data from the same sample. Place and Duration of Study: Data from the current study were collected from three secondary schools in Cornwall, UK. The first cross-section was collected in December, 2012, and the second was collected in June, 2013. Methodology: The School Information Management System was used to obtain data relating to demography (sex, school and year group attended, eligibility/ineligibility to receive free school meals, and presence/absence of a special educational needs status) and school performance (attendance, attainment at Key Stage 3/Key Stage 4 English and maths, and occurrence of behavioural sanctions). Lifestyle factors (number of sleep hours, and frequency of exercise participation) were assessed via pen and paper questionnaire. Chi-square, chi-square tests of linear association, and between-subjects t-tests were used to establish whether the school performance outcomes were associated with the demographic and lifestyle variables. These analyses were then followed-up with binary logistic regression, to determine whether the observed effects were independent of one another. Results: Low school performance was consistently associated with male sex, school and year group attended, special educational needs status, eligibility to receive free school meals, low sleep hours, and infrequent exercise participation. In addition, below average school attendance was itself predictive of low English and maths attainment, and of a high occurrence of behavioural sanctions. The majority of effects observed were significant at both the univariate and multivariate levels. Conclusions: The identification of demographic and lifestyle correlates of school performance may be useful for detecting at-risk individuals who might benefit from interventions. If such interventions were to be effective, the associated reductions in future unemployment and criminality could be beneficial to society as a whole.