Is Depression a Mental Illness? Understanding Diagnosis and Treatment

Depression is one of the most common, yet misunderstood, mental health conditions in the world. Although everyone feels sad once in a while, clinical depression or major depressive disorder (MDD) is something much deeper than a down mood. It is a serious psychiatric illness that disrupts function in everyday living, impacting a person’s emotional health, physical health, as well as interpersonal relations.

is depression a mental illness

At A Mission for Michael (AMFM), we recognize how crippling symptoms of depression can be. If you experience persistent feelings of sadness or sorrow, thoughts or feelings about suicide, or a lack of interest in doing things that once made you happy, be encouraged to know that treatment is an option—and you don’t have to face it alone. Our highly trained mental health professionals provide state-of-the-science, evidence-based treatment for every symptom of depression within our locations throughout California, Virginia, and Minnesota.

What Is Depression?

Depression is a mood disorder that impacts how you think, how you feel, and how you behave. It is a mental disorder according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), where a person is diagnosed with a major depressive episode with definite criteria.1 In contrast to situational sorrow, clinical depressive disorder is a chronic condition whose symptoms may linger for weeks, months, or even years if untreated.

Common symptoms of depression include:

  • Persistent low mood or feelings of sadness
  • Loss of interest or pleasure in most activities
  • Fatigue or lack of energy
  • Sleep disturbances (insomnia or oversleeping)
  • Appetite and weight changes (weight loss or weight gain)
  • Difficulty concentrating or making decisions
  • Feelings of worthlessness or low self-esteem
  • Physical symptoms such as chronic pain
  • Recurrent thoughts of death or suicidal thoughts

Types of Depression

There are many forms of depression, each with its own causes, risk factors, and treatment strategies. The most common types of depression include:

Major Depressive Disorder (MDD)

Also known as major depression, MDD is characterized by at least two weeks of continuous depressive symptoms that interfere with daily life.

Persistent Depressive Disorder (Dysthymia)

This form of depression involves a chronic low mood that lasts for two years or more. While symptoms may not be as severe as MDD, they are longer-lasting.

Bipolar Disorder (Bipolar Depression)

Bipolar disorder includes periods of depression alternating with manic or hypomanic episodes. Though the depressive phases resemble MDD, treatment requires different approaches.

Seasonal Affective Disorder (SAD)

SAD is a type of depression triggered by seasonal changes, most commonly in fall and winter, likely related to decreased sunlight and serotonin activity.

Postpartum Depression

This type of depression affects some women after childbirth and may include severe depression, mood swings, or psychosis in rare cases.

Psychotic Depression

This condition combines symptoms of depression with hallucinations, delusions, or disorganized thinking.

What Causes Depression?

There’s no single cause of depression—instead, it typically arises from a complex interaction of biological, environmental, and psychological factors. 

Some risk factors include:

  • Family history of depression or other mental health conditions
  • Personal history of trauma, abuse, or life events such as grief or divorce
  • Medical conditions like heart disease, or chronic illness
  • Hormonal changes (e.g., postpartum, menopause, thyroid problems)
  • Imbalances in neurotransmitters like serotonin, dopamine, and norepinephrine
  • Certain medications and their side effects
 

The American Psychiatric Association notes that depression can affect people of all ages and backgrounds, though it’s more frequently diagnosed in women.2 However, many men and adolescents may go undiagnosed due to stigma, denial, or lack of access to mental health resources.

How Depression Is Diagnosed

Depression isn’t something you can confirm with a blood test or X-ray. Diagnosis relies on clinical interviews, self-report symptoms, and standardized tools such as the PHQ-9 (Patient Health Questionnaire).3 Mental health professionals assess whether symptoms meet the criteria for major depressive disorder, including:

  • Duration: Symptoms persist for two weeks or longer
  • Frequency: Occur nearly every day
  • Impact: Interfere with work, relationships, or daily life
 

In many cases, people wait months or years before seeking help. But the earlier the diagnosis, the sooner treatment can begin—and the better the outcomes. At AMFM, we provide comprehensive psychological evaluations as part of our intake process, ensuring each client receives a personalized treatment plan built around their individual experience with depression or co-occurring disorders like anxiety or  PTSD.

Is Depression Treatable?

Yes—depression is treatable, and many people make a full recovery or achieve long-term remission with the right care. Treatment depends on the severity of the symptoms, the type of depression, and individual preferences.4 At AMFM, we offer a full continuum of care, from residential treatment to outpatient services, using evidence-based therapies that address both symptoms and root causes.

Depression Treatment at AMFM

The schizophrenia spectrum includes a number of connected disorders with overlapping symptoms:

Talk Therapy (Psychotherapy)

Psychotherapy, also known as talk therapy, is a foundational part of most depression treatment plans. It gives individuals a safe space to explore their emotions, challenge negative thinking, and build healthier coping skills. Proven modalities include:

Cognitive Behavioral Therapy (CBT)

CBT helps people recognize and reframe distorted thought patterns that lead to depressed mood. For example, turning “I’m worthless” into “I’m struggling, but I’m taking steps to get help.”

Dialectical Behavior Therapy (DBT)

Originally developed for borderline personality disorder, DBT combines mindfulness with emotion regulation and distress tolerance—especially helpful for people with suicidal ideation or impulsive behaviors.

Interpersonal Therapy (IPT)

This short-term therapy focuses on the connection between relationships and mood. It helps patients navigate grief, breakups, role transitions, and interpersonal conflict.

Trauma-Informed Therapy

When depression is rooted in childhood trauma, abuse, or PTSD, therapy must be sensitive to these experiences. Trauma-informed care focuses on safety, empowerment, and healing trust.

Transcranial Magnetic Stimulation (TMS)

TMS uses gentle magnetic pulses to stimulate areas of the brain linked to mood regulation. It’s non-invasive and often used when medications don’t provide relief. 

Medication for Depression

For many people, antidepressants are a critical piece of treatment—especially when symptoms are moderate to severe. They work by adjusting the levels of neurotransmitters in the brain, improving mood regulation and energy levels.

Types of antidepressants5 include:

  • SSRIs (e.g., Prozac, Zoloft, Lexapro): Target serotonin levels
  • SNRIs (e.g., Effexor, Cymbalta): Target serotonin and norepinephrine
  • Atypical antidepressants (e.g., Wellbutrin, Remeron): Target dopamine or other systems
 

It’s important to note: medications take time to work—usually 4–6 weeks—and may require dose adjustments or switching types. They are most effective when paired with therapy.  Our psychiatric team at AMFM closely monitors each client’s medication response and tailors the approach as needed. We never push medication but offer it as one part of a holistic plan.

When to Consider Inpatient or Residential Treatment

If depression is significantly interfering with your ability to function—or if you’ve tried outpatient treatment with no progress—inpatient care may be the right next step.

You may benefit from residential treatment if:

  • You’re experiencing suicidal ideation
  • Your symptoms are unmanageable at home
  • You’ve tried outpatient therapy without success
  • You have a co-occurring condition like bipolar disorder, PTSD, or substance use
  • You need medication adjustments in a safe, supervised setting
 

At AMFM, our residential treatment centers in California, Virginia, and Minnesota provide a peaceful, supportive environment for deep healing. Clients receive 24/7 care, a full clinical team, and a structured daily schedule that blends individual therapy, group work, family sessions, and holistic care.

Final Thoughts: You Are Not Alone in This

Depression can feel like a personal failure. But it’s not. It’s a medical condition with real treatment options, and with the right support, recovery is not only possible—it’s probable.

At A Mission for Michael (AMFM), we walk beside you through every step—from your first intake call to the moment you feel ready to thrive on your own. Whether you’re struggling for the first time, facing a recurrence, or trying to support a loved one, we’re here to help you get through it—and grow through it.

Ready to Take the Next Step?

If you or someone you love is living with symptoms of depression, don’t wait until it feels unbearable. Early treatment can make all the difference. Our team at AMFM offers personalized, evidence-based care with compassion, privacy, and hope.

Call us at (844) 309-6340 or visit our website to start the conversation.

Healing starts now.

What to Expect

Insurance Verification
Our team will verify if your insurance provider is in-network with an AMFM Healthcare Facility.

Contact From Admission Representative:
Expect a call within an hour from an admissions representative to discuss treatment options.

Hasin, Deborah S., et al. “Epidemiology of Adult DSM‑5 Major Depressive Disorder in the United States.” JAMA Psychiatry 75, no. 2 (2018): 169‑178. https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2671413

American Psychiatric Association, Depression, 2023, https://www.psychiatry.org/patients-families/depression/what-is-depression.

Sun, Y., et al. “The reliability and validity of PHQ‑9 in patients with major depressive disorder.” BMC Psychiatry 20 (2020): 1‑10. https://bmcpsychiatry.biomedcentral.com/articles/10.1186/s12888-020-02885-6

Frontiers in Psychiatry. “DSM‑5 Criteria and Depression Severity: Implications for Diagnosis and Treatment.” Vol. 9 (2018). https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2018.00450/full

National Institute of Mental Health, Mental Health Medications, 2023, https://www.nimh.nih.gov/health/topics/mental-health-medications