What is mental health?

Mental health is a foundational component of overall health, influencing how people think, feel, behave, and function throughout life. For clinicians, it shapes outcomes across nearly every medical condition. For individuals and families, it affects relationships, work, learning, physical health, and quality of life. 

Despite its importance, “mental health” is often misunderstood as either the absence of mental illness or a fixed personal trait. In reality, it is neither. Mental health also includes positive well-being, resilience, and the capacity to cope with life’s challenges; it can also be fluid throughout various life stages.  

In this article, we’ll clarify what mental health is, what it means to be mentally healthy, how mental wellness changes over time, how prevalent mental illness is in the United States, and what to do when concerns arise.

Defining mental health

The U.S. Centers for Disease Control and Prevention (CDC) defines mental health as: “the component of behavioral health that includes our emotional, psychological, and social well-being.”

Mental health affects how individuals cope with stress, relate to others, make decisions, and pursue goals. It is a dynamic state, shaped by biology, life experiences, relationships, and environment. Mental health is not simply the absence of a mental illness, but also the presence of positive well-being and functional capacity carried throughout all stages of life (image credit). 

What does it mean to be mentally healthy?

Being mentally healthy does not mean feeling happy all the time or never experiencing stress or sadness. Instead, it means:

  • Being able to cope with normal stress and daily challenges;
  • Functioning well socially, at work or school, and in relationships;
  • Having flexibility in adapting to change;
  • Being able to pursue goals and find meaning in life. 

People with good mental health can experience difficult emotions without becoming overwhelmed and can recover from setbacks. Mental health is also contextual — it is shaped by individual experiences as well as social and environmental conditions. (Source) 

Objective and subjective aspects of mental health

Mental health includes both objective and subjective dimensions:

Objective dimensions

These are observable or measurable outcomes, such as:

  • Daily functioning (school/work performance)
  • Ability to maintain relationships
  • Behavioral indicators such as sleep and appetite
  • Clinical symptom patterns

Subjective dimensions

These refer to internal personal experience:

  • Emotional balance and mood
  • Sense of life satisfaction
  • Perceived stress or distress
  • Self-esteem, hope, and sense of purpose

Effective clinical assessment considers both domains — someone may appear to function well yet still experience significant subjective distress.

How do you know if you’re mentally healthy?

Generally, someone is likely mentally healthy if they can:

  • Manage everyday stress without persistent distress;
  • Maintain meaningful relationships;
  • Function effectively at work, school, or home;
  • Adapt to life changes, including setbacks and losses;
  • Report a sense of purpose or engagement with life. 

Persistent feelings of hopelessness, severe anxiety, ongoing functional impairment, or emotional outbursts that last weeks or months may suggest poor mental health or a mental health condition.

Does mental health change over the lifespan?

As mentioned previously, mental health is dynamic and can change over the lifespan. Different phases of life can bring unique stressors and vulnerabilities. Throughout life, a person’s mental health can be influenced by a mix of predictable and unpredictable factors, including:

  • Developmental transitions (examples: childhood, adolescence, aging);
  • Biological changes (examples: hormonal shifts, injury, illness);
  • Major life events (examples: loss of a loved one, job changes);
  • Chronic stressors (examples: financial strain, family conflict).

How common are mental health problems in the US?

Mental health problems are widespread in the United States: 

  • Nearly 1 in 5 US adults will have a diagnosable mental health condition in any given year. (Source)
  • Nearly half of all Americans (about 46%) will meet criteria for a mental illness at some point in their lives. (Source)
  • About 1 in 7 U.S. youth (ages 6–17) experiences a mental health disorder annually. (Source)
  • About 50% of all lifetime mental illness begins by age 14, and 75% by age 24. (Source)

These figures emphasize that mental health conditions are common and often begin early in life, thus highlighting the importance of early recognition and treatment.

Are mental health problems more prevalent in the US than other peer countries? How about Nevada versus other states? 

Here, you might be wondering whether the US has higher per capita mental health problems relative to other peer countries. The answer appears to be yes, though cross-cultural analyses are inherently complex and challenging. 

Multiple studies have found that the US generally ranks low in both mortality (lifespan) and morbidity (healthspan – including mental health) statistics relative to other developed countries — findings which also apply to youth and adolescent populations. 

For instance, a United Health Foundation report found the following: 

“The U.S. had a higher infant mortality rate and lower life expectancy than most other OECD countries. Even the best-performing U.S. states ranked poorly among member countries for the infant mortality and life expectancy measures, despite the U.S. having the highest total health spending of all OECD countries.” 

A 2024 report from the National Academy of Sciences includes the following analyses:  

“The United States ranked 36th out of 38 countries evaluated in the 2020 UNICEF report Worlds of Influence: Understanding What Shapes Child Well-Being in Rich Countries, which focused on children’s mental wellbeing, physical health, and academic and social skills (Gromada et al., 2020). The United States ranks lowest among OECD countries for child physical health, including rates of childhood obesity (Fryar, Carroll, & Afful, 2020; Gromada et al., 2020). Additionally, the OECD 2022 Child Well-Being Dashboard ranks the United States well below average on life satisfaction among children, with only 31% of 15-year-old youth reporting high satisfaction with their life as a whole (OECD, 2022).”

There are also discrepancies in adult and youth mental health between US states. Unfortunately, Nevada consistently ranks near the bottom in such comparisons. For instance, The Annie E. Casey Foundations’ 2025 Kids Count Data Book analysis ranked Nevada 47th out of 50 states in children’s well-being. 

Clearly, there is much work to be done. Rather than succumbing to pessimism and hopelessness, we think it’s best to recognize that we can each do our part to contribute to the improvement of our own mental wellbeing and the wellbeing of our families, friends, and communities.   

What should you do if you think you or a loved one has an undiagnosed mental health problem?

For Individuals and Families

  • Seek professional evaluation: Start with a trusted health provider (e.g., primary care clinician or mental health specialist).
  • Describe symptoms clearly: Note how long symptoms have been present and how they affect daily functioning.

Access crisis support when needed: If there are thoughts of self-harm or danger to self or others, contact 988, the national Suicide & Crisis Lifeline, any time for immediate support.

For Clinicians

  • Include mental health as part of routine assessments.
  • Screen for common conditions when risk factors or symptoms are present.
  • Provide guidance on evidence-based treatments and local resources.
  • Coordinate care as needed with mental health specialists such as Nevada Pediatric Access Line (NV PAL).

Universal screening (e.g., for suicide risk) is increasingly recommended to identify individuals who might otherwise go unrecognized. See NV PAL’s Suicide Prevention Guide.

Three other important considerations:

1. Mental health and physical health are interconnected.

Mental health conditions can influence the course and outcomes of many physical illnesses, and physical health conditions can affect mental well-being. For example, according to the CDC, chronic conditions such as diabetes or heart disease are closely linked with higher rates of psychological distress.

2. Life events and risk factors matter.

Both adverse experiences (like loss, trauma, or chronic stress) and protective factors (such as social support and stable environments) profoundly influence mental health across the lifespan.

3. Stigma and access to care can negatively impact mental health.

Stigma can delay help-seeking, and access to quality mental health care remains uneven across communities. Efforts to reduce stigma and expand access are critical for improving mental health outcomes for children and adults alike.

Summary

Mental health is a holistic and dynamic part of overall health — involving emotional, psychological, and social well-being. It exists on a continuum and can change throughout life in response to internal and external influences. Mental health problems are common, often begin early in life, and deserve the same attention as physical health conditions.

Whether you are a clinician, caregiver, or member of the public, better understanding mental health can reduce stigma, promote early identification, and guide individuals to effective support and treatment.

Need help now?

If you or someone you know is struggling or in crisis, confidential, free, 24/7/365 help is available. Call or text 988 or chat 988lifeline.org. Also see the CDC’s mental health resources page.