Mental health influences how we think, feel and act — shaping how we experience life. A wide range of mental health conditions can alter our thoughts and feelings, change our behaviors, compromise other areas of our well-being, disrupt education and negatively impact relationships.

According to the World Health Organization, 1 in every 8 people in the world is living with a mental disorder. Though that organization looks at mental health statistics worldwide, Heart of Iowa Community Services strives to broaden awareness of the challenges people with mental conditions face daily right here in the region. Here we explore the most common mental illnesses that impact individuals across the globe, causes of mental illness and what are considered chronic mental health challenges.

What are the 7 most common mental illnesses?

A person is neither mentally healthy nor mentally ill. Within each of the following seven most common mental illnesses, the psychiatric disorder or mental health condition exists on a continuum, with experiences ranging from an optimal state of well-being to debilitating states of suffering and emotional pain that can fluctuate throughout the day or over extended periods of time.

Anxiety: Anxiety disorders go beyond feeling stress or nervousness that everyone experiences from time to time. Anxiety is a complex mental health condition characterized by excessive and persistent worry, fear or uneasiness — and it can manifest in various forms and intensity levels, showing up in ways that impact a person’s behavior (irritability, rumination), emotional response (avoidance, excessive fear) or physical body (muscle tension, gastrointestinal issues).

Depression: Characterized by overwhelming feelings of sadness, hopelessness, and a lack of interest or pleasure in activities, depression can be persistent and debilitating. It goes beyond typical mood fluctuations and can affect sleep, appetite and concentration. Individuals with depression may experience physical symptoms (fatigue, weight fluctuation), and it can significantly impact daily function (walking, eating) and quality of life.

Attention-Deficit/Hyperactivity Disorder (ADHD): As a neurodevelopmental disorder, ADHD can affect both children and adults, impacting various aspects of daily life. ADHD is characterized by persistent patterns of inattention (forgetfulness, wandering thoughts), hyperactivity (restlessness, excessive fidgeting or tapping) and impulsivity (interrupting, difficulty waiting) that can interfere with an individual's functioning and development.

Schizophrenia: The impact of daily functioning with schizophrenia can range from mild to severe and interferes with a person’s ability to think clearly, manage emotions, make decisions and relate to others. Although schizophrenia can occur at any age, onset tends to be in late adolescence or early adulthood and can be challenging to diagnose in teens. According to the World Health Organization’s world mental health report, schizophrenia occurs in approximately 1 in 200 adults, and in its acute states is the most impairing of all health conditions.

Borderline Personality Disorder (BPD): As a condition characterized by difficulty regulating emotion, people who experience BPD feel intensely and for extended periods of time, leading to pervasive patterns of instability in relationships, distorted self-image and difficulty trusting themselves and others. Returning to a baseline or feeling stable is harder for someone with BPD after an emotionally triggering event. Struggling with self-regulation can also result in dangerous behaviors such as self-harm.

Post-Traumatic Stress Disorder (PTSD): PTSD can occur in people who have experienced or witnessed a traumatic event such as a natural disaster, a serious accident, a terrorist act, rape, war/combat or something similar. Symptoms often involve a set of physiological and psychological responses that can lead to emotional numbing, heightened reactivity, avoidance and other disorders including alcoholism and depression.

Eating Disorders: Eating disorders are a group of food or bodyweight/body image-related conditions — including anorexia nervosa, bulimia nervosa and binge eating disorder — that cause serious emotional and physical issues. Each condition has unique symptoms separate from the others; however, all can affect people at any age or gender. Without treatment, eating disorders can take over a person’s life and lead to serious, potentially fatal medical complications.

What is the 1 most diagnosed mental disorder?

The prevalence of mental disorders varies with age and gender. In the data used by the World Health Organization in its 2019 mental health report, anxiety disorders and depressive disorders are the two most common psychiatric disorders in the world. Anxiety disorders become prevalent at an earlier age than depressive disorders, making anxiety the most common mental illness in teens.

People who experience anxiety disorders are most likely to develop symptoms before the age of 21, with approximately 7% of children aged 3–17 experiencing issues with anxiety each year.

They continue to become more common in later life, with highest estimates in people between 50 and 69. In 2019, 301 million people globally were living with anxiety disorders, and 280 million were living with depressive disorders (including both major depressive disorder and dysthymia). In 2020, these numbers rose significantly as a result of the COVID-19 pandemic.

What are the 3 most common causes of mental disorders?

The causes of mental illness are complex and multifaceted. Pinpointing specific causes for every individual can be a challenge, but the following three categories represent the most common contributing factors. For some, mental illness is caused by a combination of these or other biological, psychological and environmental factors.

Biological Factors:

  • Genetics: Family history and genetic predisposition play a significant role in the development of certain mental disorders. Individuals with a family history of mental health issues may be at a higher risk.
  • Brain Chemistry and Structure: Imbalances in neurotransmitters, the brain's chemical messengers, can influence mood and behavior. Structural abnormalities in the brain may also contribute to some mental disorders.
  • Injury: The connection between physical and mental health is well established, and injury causing pain, sustained discomfort, functional impairment or low self-esteem may impact the onset of a mental condition.

Environmental Stressors:

  • Trauma and Adverse Childhood Experiences (ACEs): Exposure to traumatic events, abuse, neglect or significant stress during childhood can increase the risk of developing mental health disorders later in life.
  • Chronic Stress: Ongoing stressors such as work pressures, financial difficulties or relationship problems can contribute to the development or exacerbation of mental disorders.
  • Substance Use: Substance use and addiction can be both a cause and a consequence of mental health disorders. Substance use can exacerbate symptoms and increase the risk of developing certain disorders.

Psychosocial Factors:

  • Social Isolation and Lack of Support: A lack of social support or feelings of isolation can contribute to the onset or worsening of mental health issues.
  • Exposures: Exposure to environmental toxins, pollutants or certain medications can impact mental health.
  • Cultural and Societal Influences: Societal pressures, cultural expectations, discrimination and stigmatization can contribute to mental health challenges.

Early intervention, comprehensive assessment and a holistic approach to treatment are crucial in managing and preventing the onset of mental illness. Understanding these factors is key to knowing how to help someone who is struggling with mental health.

What qualifies as a chronic mental illness?

The Newport Institute characterizes a chronic mental illness by conditions that consistently affect a person's cognition and/or emotions for at least three months or more long-term symptoms that persist for a year or more, significantly impacting an individual's daily life. Conditions such as schizophrenia, bipolar disorder and certain types of anxiety disorders often fall into this category. Managing chronic mental illnesses usually involves a combination of therapy, medication and support services.

By recognizing the commonality of the struggles people encounter, social norms can continue to shift toward creating more open and transparent understanding of mental health conditions and promote support and seeking professional help when it is needed. By connecting our community to what mental health resources are available, we aim to promote mental health being treated with the same importance as physical health, fostering a more inclusive future for those who experience illness of any kind.