Childhood Anxiety: The Feasibility of a School Staff Intervention and the Role of Peer Victimisation

Background: Anxiety is the most common childhood mental health difficulty and is likely to persist into adulthood without intervention. The aims of this thesis were twofold, firstly to examine the role that peer victimisation plays in anxiety development and its maintenance, and then to evaluate a newly developed school staff intervention that intends to support and prevent the escalation of childhood anxiety difficulties. Methods: A meta-analysis was conducted to examine the bidirectional effects between several types of peer victimisation and anxiety symptomatology among children and adolescents. The type of anxiety was also examined as a moderator to determine its influence. The empirical study explored the feasibility and acceptability of a newly developed psychoeducation intervention on childhood anxiety for school staff. The intervention was based on cognitive behavioural approaches and aimed to provide an overview of mild to moderate anxiety difficulties, along with strategies that could be implemented by staff within the school setting. Results: 14 studies were included in the meta-analysis, and bidirectional effects were found between all types of peer victimisation and anxiety symptoms. Relational forms of peer victimisation were shown to predict social anxiety symptoms to a greater extent than anxiety symptoms more generally. It was also found that general anxiety symptoms moderated overt types of victimisations more so than social anxiety. The empirical study recruited 76 participants in total, who rated the intervention as engaging, useful and appropriate. Participants also reported an improvement in their knowledge of childhood anxiety and increased confidence in applying anxiety strategies in their work. Preliminary efficacy findings showed that school staff responses to children’s anxious behaviours were significantly different following the intervention, as they were more likely to adopt responses and strategies supported by cognitive behavioural theory. Conclusions: Given the findings, it has been observed that peer victimisation and childhood anxiety in schools are closely linked. Psychoeducation interventions for school staff have been shown to be a feasible and acceptable method in increasing knowledge around anxiety and aids the application of strategies that may support anxious children and prevent the escalation of anxiety difficulties at school

Memantine increases the dendritic complexity of hippocampal young neurons in the juvenile brain after cranial irradiation

IntroductionCranial irradiation (IR) negatively regulates hippocampal neurogenesis and causes cognitive dysfunctions in cancer survivors, especially in pediatric patients. IR decreases proliferation of neural stem/progenitor cells (NSPC) and consequently diminishes production of new hippocampal neurons. Memantine, an NMDA receptor antagonist, used clinically to improve cognition in patients suffering from Alzheimer’s disease and dementia. In animal models, memantine acts as a potent enhancer of hippocampal neurogenesis. Memantine was recently proposed as an intervention to improve cognitive impairments occurring after radiotherapy and is currently under investigation in a number of clinical trials, including pediatric patients. To date, preclinical studies investigating the mechanisms underpinning how memantine improves cognition after IR remain limited, especially in the young, developing brain. Here, we investigated whether memantine could restore proliferation in the subgranular zone (SGZ) or rescue the reduction in the number of hippocampal young neurons after IR in the juvenile mouse brain.MethodsMice were whole-brain irradiated with 6 Gy on postnatal day 20 (P20) and subjected to acute or long-term treatment with memantine. Proliferation in the SGZ and the number of young neurons were further evaluated after the treatment. We also measured the levels of neurotrophins associated with memantine improved neural plasticity, brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF).ResultsWe show that acute intraperitoneal treatment with a high, non-clinically used, dose of memantine (50 mg/kg) increased the number of proliferating cells in the intact brain by 72% and prevented 23% of IR-induced decrease in proliferation. Long-term treatment with 10 mg/kg/day of memantine, equivalent to the clinically used dose, did not impact proliferation, neither in the intact brain, nor after IR, but significantly increased the number of young neurons (doublecortin expressing cells) with radial dendrites (29% in sham controls and 156% after IR) and enhanced their dendritic arborization. Finally, we found that long-term treatment with 10 mg/kg/day memantine did not affect the levels of BDNF, but significantly reduced the levels of NGF by 40%.ConclusionThese data suggest that the enhanced dendritic complexity of the hippocampal young neurons after treatment with memantine may contribute to the observed improved cognition in patients treated with cranial radiotherapy