Major Depressive Disorder: How It's Diagnosed and Treated

Major depressive disorder is diagnosed through a clinical evaluation, not a single blood test or scan. A clinician asks about mood, interest, sleep, energy, appetite, concentration and thoughts of death, checks how long symptoms have lasted, and looks for medical causes. Treatment usually involves psychotherapy, medication or both, adjusted over time.

This article is for adults who think they may be depressed, people recently given a diagnosis and family members who want to understand the process. It walks through the symptoms clinicians look for, what happens during an evaluation, the main treatment options, how to prepare and which warning signs need urgent care.

This article is general information, not a medical recommendation. Do not start, stop or change any medication without talking to your prescriber.

What is major depressive disorder?

It is a common, serious mood disorder that affects how you feel, think and handle daily activities. It is more than a bad week or a normal reaction to a hard event.

The American Psychiatric Association (APA) describes symptoms such as feeling sad, irritable, empty or hopeless along with loss of interest, sleep and appetite changes and trouble concentrating. The National Institute of Mental Health (NIMH) notes that genetic, biological, environmental and psychological factors play a role, and that depression can affect anyone regardless of age, background or income.

What are the symptoms of major depression?

The core symptoms are a persistently low mood or a loss of interest or pleasure in things you used to enjoy. Other symptoms often appear alongside them.

• Sadness, emptiness, hopelessness or irritability most of the day.
• Loss of interest or pleasure in hobbies, people or activities.
• Sleeping much more or much less than usual.
• Changes in appetite or weight.
• Fatigue or low energy, even after rest.
• Feeling worthless or excessively guilty.
• Trouble thinking, concentrating or making decisions.
• Moving or speaking more slowly, or feeling restless.
• Thoughts of death or suicide.

MedlinePlus notes that rather than seeming sad, men may appear angry or irritable. Depression can look different from person to person, and not everyone has every symptom.

How is major depressive disorder diagnosed?

A clinician makes the diagnosis by gathering a detailed history and comparing your symptoms with established criteria. As of October 2026, NIMH states that to be diagnosed with depression, a person must have symptoms most of the day, nearly every day, for at least 2 weeks.

The clinician also asks how symptoms affect work, school, relationships and self-care, because a change in daily functioning is part of the picture. The APA notes that symptoms must cause a clear change from your usual level of functioning. Questions often cover past episodes, family history, alcohol and drug use, trauma, stress and any history of unusually elevated mood, which matters because it can point toward a different diagnosis.

What happens during a psychiatric evaluation for depression?

An evaluation is a structured conversation that usually takes longer than a routine follow-up visit. Its goal is to understand the whole person, not just a checklist of symptoms.

The APA's practice guideline for psychiatric evaluation of adults describes a review of history, sleep and medical background, and clinicians often use short symptom questionnaires such as the PHQ-9 to measure severity and track change over time. Expect questions about:

• When symptoms began and what was happening at the time.
• Sleep, appetite, energy and concentration.
• Safety, including any thoughts of self-harm or suicide.
• Physical health, current medicines and supplements.
• Past treatment and what helped or did not help.
• Your goals and preferences for care.

You should leave with a working diagnosis or a plan to clarify it, plus agreed next steps.

Can a medical problem look like depression?

Yes. Some medical conditions and medicines can cause symptoms that look like depression, so ruling them out is part of a careful diagnosis.

MedlinePlus explains that certain medicines and medical conditions, such as viruses or thyroid disorders, may cause symptoms similar to depression. NIMH notes that a provider can rule out these possibilities with a physical exam, interview and lab tests. If you have not had a recent checkup, your psychiatric clinician may ask you to see your primary care provider for blood work.

How is major depressive disorder treated?

Treatment usually involves psychotherapy, medication or a combination, chosen based on severity, history and preference. NIMH notes that evidence-based therapies for depression include cognitive behavioral therapy and interpersonal therapy.

• Psychotherapy. Cognitive behavioral therapy helps change unhelpful thinking and behavior patterns. Interpersonal therapy focuses on relationships and life transitions.
• Medication. Antidepressants are a class of medicines used to treat depression. As of October 2026, MedlinePlus notes that they usually take 4 to 8 weeks to work, and warns never to stop them without your provider's help. Side effects vary, so talk with your prescriber about what to expect.
• Combined care. Many people do best with therapy and medication together, coordinated between clinicians.
• Daily habits. Regular sleep, movement, sunlight and connection support recovery but rarely replace treatment for moderate or severe depression.

The American Psychiatric Association states that depression is among the most treatable mental disorders, and as of October 2026 reports that between 70% and 90% of people with depression eventually respond well to treatment.

What if the first treatment does not work?

It is common to need more than one try. NIMH describes treatment-resistant depression as depression that does not improve after trying at least two antidepressants, and lists several further options.

It also helps to know that treatment is not meant to stop the moment you feel better. As of October 2026, MedlinePlus states that the typical length of antidepressant treatment is 6 to 12 months, and that stopping too fast may make depression come back. Decisions about how long to continue are made together with your prescriber, based on how you are doing.

Those options can include adjusting the plan, combining approaches, adding or changing psychotherapy and, for some people, brain stimulation treatments. A good next step is to recheck the diagnosis and look again at sleep, substance use, medical conditions and life stress. Tracking symptoms with the same questionnaire over time helps you and your clinician see whether things are actually changing.

How to prepare for your appointment: a step-by-step checklist

Preparing ahead helps you make the most of limited time. NIMH suggests noting symptoms before your visit, including when they began and how often they occur.

1. Write down your symptoms. Include when they started and how often they happen.
2. Note major changes. Losses, moves, job changes, health news or relationship stress.
3. List medicines and supplements. Include doses as written on the labels.
4. Record past treatment. What you tried, for how long and how it went.
5. Bring questions. For example: "What is my diagnosis?" "What are my options?" "How will we track progress?"
6. Consider a support person. Someone you trust can help you remember details.

What to say (example wording): "For about a month I've felt flat and exhausted, I've stopped seeing friends and I'm struggling to focus at work."

When should you get help sooner?

Some symptoms need same-day attention rather than a routine appointment. NIMH lists warning signs of suicide, including talking about wanting to die, feeling hopeless or trapped, feeling like a burden and withdrawing from others.

• Thoughts of suicide or self-harm, or making a plan: call or text 988 now.
• Immediate danger to yourself or someone else: call 911.
• Not eating or drinking, or being unable to care for yourself.
• Hearing or seeing things others do not, or severe confusion.
• Sudden worsening of mood or new agitation after starting or changing a medicine: contact your prescriber promptly.

What Texas resources can help with depression?

Texas has county-based public crisis services in addition to outpatient care. Texas Health and Human Services lists 24/7 crisis lines operated by local mental health authorities, organized by county, for people who need urgent help.

For ongoing treatment, many Texans start with a primary care provider, a therapist or a psychiatric practice. Coverage for therapy and psychiatry varies by plan, so check your benefits before your first visit. Lyte Psychiatry offers telehealth visits to patients who are physically located in Texas at the time of the visit.

Getting support in Texas

Lyte Psychiatry offers therapy, psychiatric evaluation and medication management in Texas. In-person visits are available at Lyte Psychiatry's clinic in Pantego, in the Dallas–Fort Worth area. Lyte Psychiatry offers telehealth visits to patients who are physically located in Texas at the time of the visit. All Lyte Psychiatry services are available in Spanish.

Most new patients are seen within 1–2 business days. Weekend appointments are limited. Availability, insurance and clinician fit require confirmation. Lyte Psychiatry is an outpatient practice. It does not provide inpatient care, crisis or after-hours coverage, medically supervised detox, or intensive outpatient or partial hospitalization programs.

Learn more about depression care and medication management. Related reading: what to do after a positive depression screening, what happens after a psychiatric evaluation, treatment-resistant depression and measurement-based care.

If you are in a mental-health crisis in the United States, call or text 988. Call 911 for immediate danger.

Educational information, not a diagnosis or individual treatment plan.