Mental Health

Mental health conditions affect one in five adults in the United States in any given year, according to the National Institute of Mental Health. Despite this prevalence, mental health conditions remain widely misunderstood, undertreated, and stigmatized. Quality, evidence-based information is among the most effective tools for reducing that stigma and connecting people with the care they need.

This section of Holy Rosary Healthcare covers the major mental health conditions affecting adults in the United States — their clinical definitions, prevalence, symptoms, causes, and evidence-based treatment options. All content is reviewed by Dr. Alicia Moreno, PhD, our Co-Occurring Disorders Editor, and is grounded in current clinical guidelines from the National Institute of Mental Health, the American Psychiatric Association, and peer-reviewed research.

What Is a Mental Health Condition?

Mental health conditions — also called mental disorders or psychiatric disorders — are characterized by significant disturbances in cognition, emotional regulation, or behavior that reflect a dysfunction in psychological, biological, or developmental processes underlying mental functioning. They cause significant distress or impairment in social, occupational, or other important areas of functioning.

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5-TR), published by the American Psychiatric Association, is the primary diagnostic classification system used by mental health professionals in the United States. Diagnoses are based on defined criteria that must be met in terms of symptom type, duration, severity, and functional impact.

Mental health conditions are medical conditions — not character flaws, not weaknesses, not choices. The evidence base for their neurobiological, genetic, and environmental underpinnings has grown substantially over the past three decades, even as clinical science continues to refine its understanding of their complexity.

The Intersection of Mental Health and Substance Use

Many mental health conditions frequently co-occur with substance use disorders — a combination called co-occurring disorders or dual diagnosis. According to SAMHSA's 2021 National Survey on Drug Use and Health, approximately 9.2 million adults in the United States had both a mental illness and a substance use disorder in the past year.

This intersection matters in both directions: mental health conditions increase the risk of developing substance use disorders (often as a form of self-medication), and substance use disorders can exacerbate, trigger, or mimic mental health symptoms. Effective treatment for both conditions requires understanding their interaction — which is why our Co-Occurring Disorders section is the most comprehensive part of this site.

Mental Health Conditions Covered

Evidence-Based Mental Health Treatments

Mental health conditions are treatable. The majority of people who receive appropriate, evidence-based treatment experience significant symptom reduction and improvement in quality of life. Core evidence-based treatments include:

• Cognitive Behavioral Therapy (CBT) — The most extensively validated psychotherapy across anxiety, depression, PTSD, eating disorders, and many other conditions
• Dialectical Behavior Therapy (DBT) — Developed for borderline personality disorder; now used broadly for emotional dysregulation and self-harm
• Exposure and Response Prevention (ERP) — First-line treatment for OCD
• EMDR and Prolonged Exposure — Evidence-based treatments for PTSD
• Antidepressants (SSRIs/SNRIs) — First-line pharmacotherapy for depression, anxiety disorders, PTSD, and eating disorders
• Mood stabilizers and atypical antipsychotics — Core pharmacotherapy for bipolar disorder and schizophrenia spectrum disorders
• Stimulant and non-stimulant medications — FDA-approved treatments for ADHD

For individuals with both a mental health condition and a substance use disorder, integrated treatment that addresses both simultaneously is associated with better outcomes than sequential treatment of each in isolation. See our co-occurring disorders section for detailed coverage of integrated dual diagnosis treatment.