Age-Adequate Functioning: The Key to Recovery for Youth in Mental Health Care

written by Odilia M. Laceulle, Marcel A.G. van Aken, Nagila Koster & Paul T. van der Heijden

Editorial Assistants: Chenhao Zhou and Maren Giersiepen.

Note: An earlier version of this article has been published in the Dutch version of In-Mind.

Psychological problems among youth are on the rise. In child and adolescent mental health care, awareness is growing that recovery concerns adaptive development, above and beyond symptom reduction. What role does age-adequate functioning play in youth’s well-being? And how can a developmentally oriented approach help make youth more resilient?

Figure 1.

Adaptive psychological functioning during youth can set the stage for a meaningful and healthy future. But psychological well-being cannot be taken for granted. Globally, around 1 in 7 adolescents and young adults experience a mental disorder [1]. Recent research also shows a rise in common mental disorders among Dutch youth [2]. There is growing concern about the prevalence of more severe disorders, as evidenced, for example, by increased suicidal behavior among youth. Multiple societal factors play a role, such as social media use and existential insecurity [3]. Young people place higher demands on themselves [4] and on others, and they seem to have less tolerance for mental vulnerability.

In parallel with the increase in mental disorders, mental health care has also changed. The field has shifted its perspective: treatment is no longer solely focused on symptom reduction. Instead, there is greater attention to a broader view of mental health and recovery [5]. Recovery is understood not only in terms of clinical recovery, but also personal and social recovery. Especially in youth mental health care, it is essential to look beyond symptoms alone. This helps to reduce stigma and consider the individual behind the symptoms and their context. The same symptoms can stem from very different causes: depression in a child with a chronic illness in a warm family is entirely different from depression in a healthy child whose parents are engaged in a bitter divorce and offer no support.

Broadly speaking, it is important to understand youth mental health through the lens of individual developmental trajectories, where the boundary between healthy and unhealthy mental states is often gradual and can shift over time. Age-adequate functioning—the capacity to think, feel, and behave in ways suitable for one’s age—is central to this broader perspective. The course of psychological development among vulnerable youth, and particularly age-appropriate functioning, plays a key role in their recovery and future well-being. This requires careful monitoring of the development of youth receiving mental health care.

Youth Development: Milestones and Competencies

Each life phase is characterized by its own biological, psychological, and social development. Each phase involves specific challenges and milestones. A five-year-old must learn to cooperate and share, while a twenty-year-old is developing identity and choosing a direction in life. These developmental milestones, also called developmental tasks, are central to how individuals adjust and function in society.

The concept of developmental milestones is fundamental in developmental psychology. Psychologist Erik Erikson [6] introduced the idea that each life stage is marked by a key challenge to be mastered for further growth. These challenges, such as developing trust in infancy or gaining independence in adolescence, help build essential skills needed throughout life [7]. Successfully navigating these milestones is crucial for healthy development. Failure to do so can lead to long-term problems, such as relationship difficulties or struggles in maintaining employment.

The Relationship Between Development and Recovery

It has long been recognized in youth mental health care that mental health encompasses more than the presence or absence of mental disorders. Youth facing mental disorders, such as anxiety, depression, or personality disorders, often struggle to achieve developmental milestones (e.g., autonomy or academic functioning). This can lead to a vicious cycle: psychological issues hinder development, and stagnation in development worsens the symptoms. The concept of age-adequate functioning can help shed light on, and ultimately provides a way to break this cycle. By assessing how well youth fulfill age-specific tasks, practitioners can support recovery in a more holistic way, addressing well-being and quality of life, not just symptom reduction. For example, instead of asking only “How are your anxiety or depression symptoms?” care providers can ask: “How are things at school? How are your friendships? Can you make independent decisions?” Such questions are crucial for tailoring care to developmental needs.

Mental health care for youth must take into account their stage of development. Youth who experience stagnation need interventions that not only reduce symptoms but also support growth and functioning. This approach enables more personalized care: some youth need help with social skills; others need guidance in choosing a life direction or gaining autonomy from parents. This aligns with a broader movement toward developmentally informed, life-stage-sensitive care [8, 9].

Moreover, a developmental lens allows for more youth participation in treatment decisions. Youth can indicate where they want to make progress and which areas are priorities. This helps providers and youth collaboratively set goals and tailor care accordingly. It also clarifies who else is needed in the recovery process: What do I need from my parents? What do my parents need to support my development? How can teachers contribute?

Neurodiversity and Mental Health

In recent years, more attention has been paid to neurodiversity—a perspective that sees characteristics like ADHD and autism not as disorders in the traditional sense, but as variations in how people think and function. While not the core focus of this paper, this perspective fits within the broader shift toward seeing mental health not only as the absence of symptoms, but as the capacity to grow through one’s unique strengths and challenges. A developmental approach helps tailor support to youth's individual needs, fostering a more inclusive approach that recognizes both recovery and diversity in functioning.

Measuring Age-Adequate Functioning

The focus on age-adequate functioning is part of a wider movement in mental health care, with recovery becoming its central focus. In adult mental health care, several tools already exist to measure recovery across life domains such as work, relationships, and health [10]. This broad view on recovery aligns well with the needs of youth. But a truly developmental perspective requires careful monitoring. Notably, an adequate tool must reflect the extent to which young people are achieving (or going through) age-adequate developmental milestones.

The Developmental Milestones List (OML; available on request)—a recently developed 21-item questionnaire that assesses age-adequate personal, social, and academic/professional functioning—offers such a developmental method. A recent study among youth aged 12 to 24 with various psychological complaints (e.g., anxiety, mood, or personality issues) showed that the OML provides clear insight into general functioning and correlates strongly with symptom severity [11]. Youth who function better on the OML typically report fewer psychological complaints. By assessing how well youth complete developmental tasks, practitioners can better understand their current functioning and predict their resilience in facing future challenges.

The introduction of a developmentally oriented perspective in psychological care, along with tools to effectively assess it, can lead to more tailored treatments and support, taking into account each young person’s specific developmental stage and needs, as well as enabling adequate evaluation of these treatments. This not only benefits the individual youth, but also provides important advantages for society as a whole. Young people who function well and develop resilience are more likely to find their place in this complex society and make their unique contribution. By continuing to build on these ideas in the future, mental health care can better support young people in their recovery and help them reach their full potential, ultimately contributing to a healthier and more resilient society.

Conclusion

Age-adequate functioning is a key concept in understanding and promoting mental health among youth. It offers a developmental approach that goes beyond symptom reduction and focuses on how youth grow and evolve within their life stage. By carefully tracking developmental milestones and supporting youth in achieving them, we increase their chances of building a meaningful and fulfilling future. This not only benefits the individual, but also society at large. Integrating a developmental perspective in mental health care and other youth-supporting contexts is an essential step toward more effective, personalized, and future-focused care for young people.

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