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Featured researches published by Gemma Lewis.


PLOS ONE | 2016

Friendships and Family Support Reduce Subsequent Depressive Symptoms in At-Risk Adolescents

Anne-Laura van Harmelen; Jenny Gibson; Michelle C. St Clair; Matthew Owens; Jeannette Brodbeck; Valerie Dunn; Gemma Lewis; Tim Croudace; Peter B. Jones; Rogier A. Kievit; Ian M. Goodyer

Background Early life stress (ELS) consists of child family adversities (CFA: negative experiences that happened within the family environment) and/or peer bullying. ELS plays an important role in the development of adolescent depressive symptoms and clinical disorders. Identifying factors that may reduce depressive symptoms in adolescents with ELS may have important public mental health implications. Methods We used structural equation modelling and examined the impact of adolescent friendships and/or family support at age 14 on depressive symptoms at age 17 in adolescents exposed to ELS before age 11. To this end, we used structural equation modelling in a community sample of 771 adolescents (322 boys and 477 girls) from a 3 year longitudinal study. Significant paths in the model were followed-up to test whether social support mediated or moderated the association between ELS and depressive symptoms at age 17. Results We found that adolescent social support in adolescence is negatively associated with subsequent depressive symptoms in boys and girls exposed to ELS. Specifically, we found evidence for two mediational pathways: In the first pathway family support mediated the link between CFA and depressive symptoms at age 17. Specifically, CFA was negatively associated with adolescent family support at age 14, which in turn was negatively associated with depressive symptoms at age 17. In the second pathway we found that adolescent friendships mediated the path between peer bullying and depressive symptoms. Specifically, relational bullying was negatively associated with adolescent friendships at age 14, which in turn were negatively associated with depressive symptoms at age 17. In contrast, we did not find a moderating effect of friendships and family support on the association between CFA and depressive symptoms. Conclusions Friendships and/or family support in adolescence mediate the relationship between ELS and late adolescent depressive symptoms in boys and girls. Therefore, enhancing affiliate relationships and positive family environments may benefit the mental health of vulnerable youth that have experienced CFA and/or primary school bullying.


The Lancet Psychiatry | 2017

The association between paternal and adolescent depressive symptoms: evidence from two population-based cohorts

Gemma Lewis; Martha Neary; Ela Polek; Eirini Flouri; Glyn Lewis

BACKGROUNDnIncidence of depression increases markedly around age 13 years, and nearly three-quarters of adults report that their mental health problems started in adolescence. Although maternal depression is a risk factor for adolescent depression, evidence about the association between paternal and adolescent depression is inconclusive, and many studies have methodological limitations. We aimed to assess the association between paternal and adolescent depressive symptoms in two large population-based cohort studies.nnnMETHODSnWe used data for two-parent families from two representative prospective cohorts in Ireland (Growing up in Ireland [GUI]) and the UK (Millennium Cohort Study [MCS]). Parental depressive symptoms were measured with the Centre for Epidemiological Studies Depression Scale in the GUI cohort when children were 9 years old, and the Kessler six-item psychological distress scale in the MCS cohort when children were 7 years old. Adolescent depressive symptoms were measured with the Short Mood and Feelings Questionnaire (SMFQ) at age 13 years in the GUI cohort and age 14 years in the MCS cohort. We analysed data using linear regression models, before and after adjustment for confounders, in both multiply imputed and complete case samples.nnnFINDINGSnThere were 6070 families in GUI and 7768 in MCS. After all adjustments, a 1 SD (three-point) increase in paternal depressive symptoms was associated with an increase of 0·24 SMFQ points (95% CI 0·03-0·45; p=0·023) in the GUI cohort and 0·18 SMFQ points (0·01-0·36; p=0·041) in the MCS cohort. This association was independent of, and not different in magnitude to, the association between maternal and adolescent depressive symptoms (Wald test p=0·435 in the GUI cohort and 0·470 in the MCS cohort).nnnINTERPRETATIONnOur results show an association between depressive symptoms in fathers and depressive symptoms in their adolescent offspring. These findings support the involvement of fathers as well as mothers in early interventions to reduce the prevalence of adolescent depression, and highlight the importance of treating depression in both parents.nnnFUNDINGnDepartment of Children and Youth Affairs and Economic and Social Research Council.


Social Psychiatry and Psychiatric Epidemiology | 2016

The ROOTS study: a 10-year review of findings on adolescent depression, and recommendations for future longitudinal research

Gemma Lewis; Peter B. Jones; Ian M. Goodyer

PurposeThe purpose of this study is to review longitudinal findings on adolescent mental health from the ‘ROOTS study’, and provide directions and recommendations for future longitudinal research. To do this, we discuss relevant findings from the ROOTS study, and review its strengths and limitations.MethodsWe examined all publications from the ROOTS study up to July 2015, selected those examining adolescent mental health, and classified them as investigating (a) childhood risk factors for adolescent depression, (b) genetic and cognitive vulnerability to depression in adolescence, (c) genetic markers, childhood adversities, and neuroendophenotypes, (d) morning cortisol and depression, (e) physical activity and depression symptoms, and (f) the underlying structure of mental health in adolescence. We reviewed the strengths and limitations of the ROOTS study, and how they feed into recommendations for future longitudinal research.ResultsThere was evidence supporting a putative hormonal biomarker for the emergence of depression in boys. Environmental pathways from child adversity to adolescent depression were confirmed in girls, partly accounted for by negative life events in early adolescence. The preceding role of automatic cognitive biases assessed using behavioural tasks was substantiated, with evidence for genetic susceptibility. Novel latent statistical models of child adversity, depression, anxiety, and psychotic experiences were produced, with concurrent and prospective validity. Our experiences conducting the ROOTS study resulted in a set of strengths, limitations, and recommendations for future longitudinal studies.ConclusionsThe ROOTS study has advanced knowledge on the aetiology of adolescent depression by investigating environmental, genetic, hormonal, and neural risk factors. Findings provide a foundation for future research integrating cognitive neuroscience with epidemiology.


Journal of Affective Disorders | 2015

Examining reward-seeking, negative self-beliefs and over-general autobiographical memory as mechanisms of change in classroom prevention programs for adolescent depression

Frances Rice; Adhip Rawal; Lucy Riglin; Gemma Lewis; Glyn Lewis; Sandra Dunsmuir

Background Effective methods to prevent adolescent depressive symptoms could reduce suffering and burden across the lifespan. However, psychological interventions delivered to adolescents show efficacy only in symptomatic or high-risk youth. Targeting causal risk factors and assessing mechanistic change can help devise efficacious universal or classroom based prevention programs. Methods A non-randomized longitudinal design was used to compare three classroom-based prevention programs for adolescent depression (Behavioral Activation with Reward Processing, “Thinking about Reward in Young People” (TRY); Cognitive Behavioral Therapy (CBT) and Mindfulness Based Cognitive Therapy (MBCT)), and determine cognitive mechanisms of change in these programs. Cognitive mechanisms examined were reward-seeking, negative self-beliefs (assessed with behavioral tasks) and over-general autobiographical memory. 256 healthy adolescents aged 13–14 participated with 236 (92%) and 227 (89%) completing the pre- and post-assessments. Results TRY was the only intervention associated with a reduction in depressive symptoms at follow-up. Reward-seeking increased following TRY. In the other programs there were non-significant changes in cognitive mechanisms, with more reflective negative self-beliefs in CBT and fewer over-general autobiographical memories in MBCT In the TRY program, which focused on increasing sensitivity to rewarding activities, reward seeking increased and this was associated with decreased depressive symptoms. Limitations Due to the infeasibility of a cluster randomized controlled trial, a non-randomized design was used. Conclusions Increased reward-seeking was associated with decreased depressive symptoms and may be a mechanism of depressive symptom change in the intervention with a focus on enhancing sensitivity and awareness of reward. This study provides preliminary evidence to suggest that incorporating activities to enhance reward sensitivity may be fruitful in randomized controlled trials of universal prevention programs for depression.


Acta Psychiatrica Scandinavica | 2017

Variation in the recall of socially rewarding information and depressive symptom severity: a prospective cohort study

Gemma Lewis; Daphne-Zacharenia Kounali; Katherine S. Button; Larisa Duffy; Nicola J Wiles; Marcus R. Munafò; Catherine J. Harmer

To test the association between recall for socially rewarding (positive) and/or socially critical (negative) information and depressive symptoms.


Translational Psychiatry | 2018

GSK3β: a plausible mechanism of cognitive and hippocampal changes induced by erythropoietin treatment in mood disorders?

Becky Inkster; Gwyneth Zai; Gemma Lewis; Kamilla W. Miskowiak

Mood disorders are associated with significant psychosocial and occupational disability. It is estimated that major depressive disorder (MDD) will become the second leading cause of disability worldwide by 2020. Existing pharmacological and psychological treatments are limited for targeting cognitive dysfunctions in mood disorders. However, growing evidence from human and animal studies has shown that treatment with erythropoietin (EPO) can improve cognitive function. A recent study involving EPO-treated patients with mood disorders showed that the neural basis for their cognitive improvements appeared to involve an increase in hippocampal volume. Molecular mechanisms underlying hippocampal changes have been proposed, including the activation of anti-apoptotic, antioxidant, pro-survival and anti-inflammatory signalling pathways. The aim of this review is to describe the potential importance of glycogen synthase kinase 3-beta (GSK3β) as a multi-potent molecular mechanism of EPO-induced hippocampal volume change in mood disorder patients. We first examine published associations between EPO administration, mood disorders, cognition and hippocampal volume. We then highlight evidence suggesting that GSK3β influences hippocampal volume in MDD patients, and how this could assist with targeting more precise treatments particularly for cognitive deficits in patients with mood disorders. We conclude by suggesting how this developing area of research can be further advanced, such as using pharmacogenetic studies of EPO treatment in patients with mood disorders.


PLOS ONE | 2018

The association between pubertal status and depressive symptoms and diagnoses in adolescent females: A population-based cohort study

Gemma Lewis; Konstantinos Ioannidis; Anne-Laura van Harmelen; Sharon Neufeld; Jan Stochl; Glyn Lewis; Peter B. Jones; Ian M. Goodyer

Background There is an association between puberty and depression, but many things remain poorly understood. When assessing puberty in females, most studies combine indicators of breast and pubic hair development which are controlled by different hormonal pathways. The contributions of pubertal timing (age at onset) and pubertal status (stage of development, irrespective of timing) are also poorly understood. We tested the hypothesis that stage of breast development in female adolescents, controlled largely by increased estradiol, would be more strongly associated with depression than pubic hair development which occurs in both males and females, and is controlled by adrenal androgens. We investigated whether this association was independent of pubertal timing. Methods ROOTS is an ongoing cohort of 1,238 adolescents (54% female) recruited in Cambridgeshire (UK) at age 14.5, and followed-up at ages 16 and 17.5. Depression was assessed using the Mood and Feelings Questionnaire (MFQ) and clinical interview. Breast and pubic hair development were assessed at 14.5, using Tanner rating scales. Results For each increase in Tanner breast stage at 14.5, depressive symptoms increased by 1.4 MFQ points (95% CI 0.6 to 2.3), irrespective of age at onset. Pubic hair status was only associated with depressive symptoms before adjustment for breast status, and was not associated with depression in males. The same pattern was observed longitudinally, and for depression diagnoses. Limitations We did not directly measure hormone levels, our findings are observational, and the study had a relatively low response rate. Conclusions Females at more advanced stages of breast development are at increased risk of depression, even if their age at pubertal onset is not early. Alongside social and psychological factors, hormones controlling breast but not pubic hair development may contribute to increased incidence of female depression during puberty.


Journal of Child Psychology and Psychiatry | 2018

The association between paternal depressogenic cognitive styles during pregnancy and offspring depressogenic cognitive styles: an 18-year prospective cohort study

Gemma Lewis; Siying Wen; Rebecca M Pearson; Glyn Lewis

Background Preventing the development of depressogenic or negative cognitive styles could also prevent the development of depression, a leading public health problem worldwide. Maternal negative cognitive styles are a modifiable risk factor for the development of negative cognitive styles in offspring. However, evidence on the role of paternal negative cognitive styles is inconclusive and there have only been a few small studies, which may also have lacked statistical power. Methods We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC) to investigate the association between paternal negative cognitive styles, measured when mothers were 18 weeks pregnant, and offspring negative cognitive styles 18 years later (N = 6,123). Associations were calculated using linear regression models, before and after adjustment for confounders including maternal negative cognitive styles. We compared associations before and after controlling for depression in parents and offspring, and used multiple imputation to reduce biases that may have arisen due to missing data. Results A two‐standard deviation increase in paternal negative cognitive style was associated with a 3‐point increase in offspring negative cognitive style (95% CI 1.36–4.37). This association remained after adjustment for confounders and was independent of depression in both parents and offspring. The effect size was equivalent to that of maternal negative cognitive style, and was also independent of maternal negative cognitive style. Conclusions Our results suggest that fathers should be included in individual‐ and family‐based interventions designed to prevent the development of depressogenic cognitive styles in adolescent offspring. This could possibly also prevent the development of depression.


Archive | 2016

The Rest Test: Preliminary Findings from a Large-Scale International Survey on Rest

Claudia Hammond; Gemma Lewis

In this chapter, Claudia Hammond and Gemma Lewis discuss The Rest Test, the world’s largest survey into people’s subjective experiences of rest, devised by an interdisciplinary team at Hubbub. The Rest Test was launched in collaboration with the BBC on Radio 4’s All in the Mind, presented by Claudia, who played a key role in the survey development. Gemma led the analysis of The Rest Test results.


The Lancet Psychiatry | 2018

Paternal and maternal depression and offspring risk: additive effects or worse? – Authors' reply

Gemma Lewis; Martha Neary; Ela Polek; Eirini Flouri; Glyn Lewis

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Glyn Lewis

University College London

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Martha Neary

Northwestern University

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Ela Polek

University College Dublin

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Adhip Rawal

University College London

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