Adolescence and young adulthood make up a singular time in an individual’s life, in terms of both the amount of change that occurs and the personal evolution prompted by learning about oneself and our relationships with others and the world around us. It can also be amorphous. There is no definite age boundary on adolescence, although it is anchored to the onset of puberty. But by most definitions, including that of the World Health Organization, the boundaries are between ages 10 and 19. The period after, or ‘young adulthood’, generally covers ages 19–25.

Modern conceptualizations of adolescence and young adulthood go beyond age ranges and include well-developed theories that describe the numerous changes that individuals undergo during this period, including physical and neurobiological maturation, psychological and cognitive development, and heightened emotional lability. Perhaps not as simple as the picturesque “sturm und drang” (storm and stress) model put forth by G. Stanley Hall, the twentieth century American psychologist who is credited with establishing the study of the adolescent developmental period, but remnants of this description persist.

Across many fields that study mental health in adolescence and young adulthood, there is an acknowledgment that this time in an individual’s life is marked by the complex interplay between new experiences and environments and one’s emotional and cognitive responses. The experience and expression of emotions that arise for young people can be overwhelming, especially in light of newly developing regulatory mechanisms. And although heightened emotionality can be part of normative or typical development, adolescence, in particular, is often the time when mental health difficulties emerge. In addition to depression and anxiety, other psychiatric illnesses commonly present during adolescence, including obsessive-compulsive disorder, schizophrenia, eating disorders and substance-use disorders.

At the same time that an awareness has grown among healthcare providers, parents, educators and young people themselves, plus decades of adolescent and young adult psychopathology research, there is an alarming global trend of increasingly adverse youth mental health. Recent estimates1 indicate that 25% of people under age 18 have experienced increased symptoms of depression, which is double the proportion from before the COVID-19 pandemic. Suicidality, including ideation and attempts, has risen in recent years, and suicide is the second leading cause of death among people aged 15–19 globally.

The rapid rise in negative mental health outcomes in young people has prompted health and government policymakers to refer to the present situation as a youth mental health “crisis”. In 2021, the US surgeon general added youth mental health to one of its current priorities and released the ‘Protecting youth mental health’ report2, detailing a multisectoral advisement on mitigating harms from the pandemic, social media and stigma. This year, the European Commission published its public health plan ‘A comprehensive approach to mental health’3, which underscores more consideration of social determinants of health that affect young people, such as nutrition and access to alcohol and tobacco, as part of its focus on prevention of mental health disorders. Even with considerable focus on the potential role of the pandemic as a magnifier of mental health inequities and disruption and isolation for young people, there is concern that many negative changes have been in play for at least a decade, according to US Centers for Disease Control and Prevention data from 2011–2021 showing that young female, LGBT+ and people of color have experienced increased rates of violence, suicidality and substance use over time4. The pandemic has forced a reckoning on a global scale that youth mental health is in jeopardy, but recognizing the warning signs can be complex and challenging. Given the impact of youth mental health on influencing the trajectory of mental health and wellbeing across the lifespan, it is essential that we improve how mental health problems are identified for prevention, as well as how to implement interventions earlier.

In this month’s issue of Nature Mental Health, we include an assortment of original primary research and commentary that highlight important findings and provide advances in understanding the course of youth mental health disorders, from detection to intervention.

In the ‘front half’ of the journal, senior editor Ana Donnelly has a Q&A with Christian Kieling, an associate professor of child and adolescent psychiatry in Brazil, about his work on the Identifying Depression Early in Adolescence (IDEA) project, using a range of methods, including psychoneuroimmunology, imaging and qualitative research, to stratify risk for developing depression in adolescence. In a Perspective piece, Anne Duffy introduces us to children of parents with severe mental illness, who are themselves at increased risk of developing a mental illness, but who may benefit from developmentally sensitive interventions. Associate Editor Natalia Gass reports in a Research Highlight on new work from Yun-Jun Sun, Barbara Sahakian et al., finding that reading for pleasure in childhood was associated with greater academic achievement and cognitive performance and negatively correlated with psychopathology scores and mental health problems, concluding that reading for pleasure could be a useful mental health intervention owing to its scalability and relatively low cost.

Also in this issue, we publish original research on the patterns of violence and mental health outcomes in young adults both before and during the COVID-19 pandemic. In an Article, Wisteria Deng and coauthors sample more than 200,000 college students in the USA, and found greater levels of depressive and anxiety symptoms and increased numbers of sexual violence and assaults experienced by people from gender and sexual minorities during the pandemic. These data reinforce the disproportionate and heightened mental health and sexual violence risks for young people from gender and sexual minorities and the need to increase on-campus safety and crisis intervention. Two other papers out this month use different techniques to investigate psychiatric biomarkers. Margaret Westwater and colleagues report findings that show that the genetic risk for disordered eating was associated with distinct brain structure differences and symptom profiles in a sample of more than 4,900 adolescents. Using plasma-based proteomics, Katja Kanninen and coauthors present some of the first work in identifying protein alteration biomarkers associated with the risk of developing a mental health disorder.

Much of the work published now may not be immediately actionable in a real-world setting, yet it provides clear directive for where a more solid evidence base is needed — for example, with more representative participants or country settings. It also can be extremely valuable in determining where the thresholds for clinical utility of biomarkers should be placed, such as during routine screening programs or potentially at younger ages. In the face of the youth mental health crisis, concurrently pursuing several lines of inquiry is essential. From neurobiological markers, school-based interventions and social determinants of health to reducing stigma, changing the course of the youth mental health crisis will require all of the tools that we have available.