Mood disorders are a leading cause of illness and disability in children and adolescents. Effective treatment is available, and early identification and intervention improves prognosis. This chapter provides a comprehensive summary of the epidemiology, aetiology and clinical features of depression and bipolar disorder in young people. We provide evidence-based recommendations for the prevention and treatment of mood disorders in children and adolescents, including psychological and pharmacological interventions, and novel and emerging treatment options. We present research on predictors of treatment outcome and prognosis of mood disorders in young people, and highlight areas for further research. This chapter will help clinicians identify and treat young people with mood disorders in a range of clinical settings.

This chapter reviews a broad spectrum in Child and Adolescent Mental Health; that of the anxiety disorders. The chapter briefly introduces the concept of attachment and touches on how attachment disorders, and attachment styles evolve. It focuses in on PTSD and C-PTSD, with a particular spotlight on C-PTSD as a new diagnostic concept, and considers its importance in understanding presentations of trauma and emotional dysregulation in children and young people. The chapter also investigates the epidemiology and course of anxiety disorders; and considers the differentiating features of the different presentations. We finish with an overview of interventions, including the rise of computerised approaches in treating the anxiety disorders in young people.

A survey found that 1 in 6 (16%) of children aged between 5 and 16 years has a probable mental illness. Furthermore, research has shown that most of these disorders have their origins in childhood, even if they are typically diagnosed in adulthood. Childhood represents a critical period of physical, cognitive, psychological, behavioural and social transformation. Identifying risk and protective factors that alter the typical developmental trajectory could have long-term educational, social, societal and economic implications. This chapter will address what is meant by the term risk factor and how these can be identified, provide examples of risk factors thought to be important in child and adolescent psychiatry. It concludes with some case vignettes to highlight the importance of taking a developmental biopsychosocial approach to identifying risk, considering predisposing, precipitating, perpetuating and protective factors.

Infancy is a time of great opportunity and hope. The mental health of infants is key to the health and wellbeing of society as a whole. Psychiatrists have an important role to play in this field of psychiatry, and knowledge in infant mental health is foundational to all specialties.This chapter describes the importance of infant mental health and explores the theoretical underpinnings of the specialty. The case for infant mental health services is discussed along with a needs-led approach to the provision of services. Clinical assessment and intervention are described broadly with examples of common intervention modalities.

This chapter provides an overview of neurodevelopmental disorders (NDDs) in children and young people. The definition and classification of NDDs is discussed, including key differences between ICD-10 and ICD-11 and the problematic use of language in diagnostic classifications, which is at odds with the social model of disability. Important stages of a multidisciplinary assessment of NDDs include a detailed developmental history, a psychosocial history, observation of the child, an assessment of the child’s communication and learning and supplementary rating scales. The role of professionals such as Community Paediatricians, Speech and Language Therapists, Occupational Therapists, teachers and Educational Psychologists is highlighted. Features of the main NDDs are outlined, including Autism Spectrum Disorder, Attention Deficit Hyperactivity Disorder, Specific Disorders of Development and Language and Tic disorders. Finally, an overview of treatment approaches and their evidence base is explored.

Eating disorders are complex conditions that pose significant challenges for diagnosis and treatment. Recent updates to diagnostic criteria in the DSM-5 and ICD-11 have refined our understanding of eating disorders, underscoring the need for early intervention to improve recovery outcomes. This chapter reviews these changes and their implications for clinical practice. We explore the increasing complexity of eating disorder presentations, particularly those involving neurodevelopmental and personality disorders, which require nuanced treatment approaches. Additionally, the chapter examines the impact of social media on eating behaviours, highlighting both the negative influences and the potential benefits of online resources. The rise of digital therapies, especially in response to the Covid-19 pandemic, is discussed as a key development in expanding access to care. The chapter also addresses the evolving clinical presentation of eating disorders, noting that conditions like binge eating disorder, other specified feeding or eating disorders, and avoidant restrictive food intake disorder are now more common. To meet the needs of young people, we advocate for improved community care, public health strategies and further research into effective treatments. This chapter emphasises the urgent need to enhance recognition and support for ED across health care systems and community settings.

The concept of prevention in health and welfare has long been recognised as crucial, yet its practical implementation remains complex. This chapter delves into the significance of prevention as a fundamental principle in addressing societal challenges and individual health outcomes. With a focus on the links between adversity, societal issues and health burdens, the economic rationale for preventive measures becomes apparent. Recent attention has been drawn to prevention and early intervention, particularly in light of the long-term consequences of early adversity on physical and mental health. Government initiatives in the UK, such as the establishment of Health and Wellbeing Boards and emphasis on prevention in health services, underscore the growing importance of prevention strategies. The impact of the Covid-19 pandemic has further highlighted the need for proactive prevention measures in health and welfare policies. This chapter explores the meaning of prevention, theoretical considerations, practical clinical strategies and the role of senior health professionals in promoting prevention in children’s mental health services.

Children and young people’s mental health services continue to remain a high priority for government and the NHS. Delivering good outcomes for young people will require coordinated action across health, education, third sector and local government departments and between national and local bodies. There are opportunities through increased investment and more collaborative commissioning and service delivery arrangements to deliver a systems wide approach to providing care for children and young people. The COVID-19 pandemic has affected everyone although children and young people have been disproportionately adversely affected, as they have had to adapt to extraordinary changes to the world around them. New models of care can stimulate effective collaboration between commissioners and providers to develop integrated, accessible services for all in community based settings. Expanding access through digital support can enable more people to receive effective care providing greater accessibility and choice. A focus on quality improvement can support staff and patients to improve care through effective use of data, with support from professional networks. However, all new models must be developed in partnership with experts-by-experience, carers, and community and voluntary organisations. Systemic investment in services and the staff who provide them is needed to meet the ambitions set by governments.

Gender diversity is relatively common in youth, with rates increasing in the general population. This increase may be related to decreased stigma in gender expression, adolescent experimentation, environmental factors or due to the recent interest in quantitatively measuring this trait. Gender diversity in and of itself is a not a psychiatric disorder. But mental health providers might see gender diverse youth if there is the desire for gender-affirming treatment, for assessing and treating of co-occurring psychiatric disorders or to promote resilience in situations where bullying and stigmatisation are taking place. As such, clinicians should be prepared to provide a confidential and competent environment that recognises the vast range of gender diversity currently seen in youth. In addition, while research on mental health in gender diverse youth has substantially expanded in the past decade, limitations of these data influence interpretation and generalisability. Well-designed studies should address gaps, such as long-term follow-up periods for gender diverse youth and those who have received gender affirmative care. They should also examine developmental trajectories and the stability of gender identity. Gender diversity in racial and ethnic minorities who may have different psychiatric presentations should also be addressed in future research.

Bodily Distress Disorder and Dissociative Disorders are disorders frequently encountered across paediatric specialties. These disorders place high psychosocial, educational and financial strains on children and their families as well as a substantial burden on the health care system with a potential risk for iatrogenic harm to the child due to unnecessary diagnostic evaluations and fruitless treatment attempts leading to increased costs. Predisposing factors include neurodevelopmental disorders and often co-morbidities such as anxiety and depression exist. The current best evidence-based treatment is psychological interventions that involve active participation from both the child and the parents. As early diagnostics and relevant intervention may improve prognosis and potentially decrease the risk of continued persistent and disabling somatic and co-occurring psychiatric symptoms later in life, it is important to address these disorders in young people. Due to the particular characteristics of somatic complaints combined with a high risk of psychiatric co-morbidities and specialised psychological interventions as best evidence-based practice, the diagnostics and treatment should optimally take place in close collaboration between the paediatric/medical setting and child and adolescent psychiatry.

Clinicians navigating the legislation when working with young people and their families in the United Kingdom (UK) may need to use several relevant frameworks of legislation at the same time. This may appear complex in practice. Clinicians need to consider how a young person’s development across multiple domains, for example, cognitive, emotional, moral, social and so on, can have an impact upon their decision-making. Clinicians who work with children and young people often also work with parents or their local authority statutory equivalents, as well as other statutory and non-statutory agencies, to help find the best outcomes for children and young people (CYP). This requires good knowledge of legal frameworks, competence in working within complex multi-agency systems and being able to understand and work with different perspectives around an issue.This chapter specifically discusses aspects of the law in relation to children and adolescents (all those under 18 years) including the Human Rights Framework, Mental Capacity Act 2005, Children Act 1989 (amended 2004), Mental Health Act (amended 2007), and Criminal Justice Act (2003) within England and Wales. We have not addressed the differences in legislation in Northern Ireland or Scotland but have commented on distinct issues where relevant.