What Causes Depression? Symptoms and Treatment Basics

What causes depression is usually a mix of factors rather than one thing: genetics and family history, brain biology, stressful or traumatic life events, medical conditions, certain medicines and substance use. Depression is a common, treatable condition, not a character flaw. Most people improve with therapy, medication or both, and an evaluation is a good first step.

This guide is for adults in Texas who wonder whether what they feel is depression, and for family members who want to understand it. It covers causes, symptoms, how depression is diagnosed and treated, what to tell a clinician and when to get help sooner. This article is general information, not a medical recommendation. Do not start, stop or change any medication without talking to your prescriber.

What is depression?

Depression is a mood disorder that causes persistent sadness, emptiness or loss of interest, along with changes in sleep, appetite, energy and thinking. The American Psychiatric Association (APA) describes depression as a common and serious condition, with symptoms that last most of the day nearly every day for more than two weeks and cause a change in functioning.

Depression comes in several forms. The National Institute of Mental Health (NIMH) lists types including major depression, persistent depressive disorder, seasonal affective disorder and perinatal depression, among others. A clinician can help clarify which, if any, fits your experience.

What causes depression?

Depression has no single cause. NIMH states that research suggests genetic, biological, environmental and psychological factors play a role. These factors often interact, so two people with similar life events may respond very differently.

• Genetics and family history: depression can run in families, though having a relative with depression does not mean you will develop it.
• Biology: differences in brain function, hormones and sleep regulation can contribute.
• Life events: loss, divorce, job loss, trauma, caregiving and chronic stress can trigger episodes.
• Medical illness: chronic pain, heart disease, thyroid problems and other conditions are linked with depression.
• Medicines and substances: some medications and heavy alcohol or drug use can bring on or worsen symptoms.
• Psychological patterns: long-standing self-criticism, perfectionism or low self-esteem may raise risk.

Can a medical condition or medication cause depression?

Yes, some medical conditions and medicines can cause or worsen depression symptoms, which is why a full evaluation matters. MedlinePlus notes that certain medicines and some medical conditions, such as viruses or thyroid disorders, can cause the same symptoms as depression.

Hypothyroidism is one example. MedlinePlus lists fatigue, weight gain and depression among its symptoms, and it is diagnosed with blood tests. Alcohol also matters: the Centers for Disease Control and Prevention (CDC) notes that excessive alcohol use can lead to mental health conditions including depression. Our guide to conditions confused with depression covers more look-alikes.

What are the symptoms of depression?

Common symptoms of depression include persistent sadness or emptiness, loss of interest or pleasure, and changes in sleep, appetite and energy. NIMH lists symptoms such as hopelessness, irritability, fatigue, difficulty concentrating, and thoughts of death or suicide.

• Feeling sad, empty, numb or hopeless most days.
• Losing interest in hobbies, friends or sex.
• Sleeping much more or much less than usual.
• Changes in appetite or weight.
• Moving or speaking more slowly, or feeling restless.
• Guilt, worthlessness or harsh self-criticism.
• Trouble concentrating or making decisions.

Depression can look different from person to person. MedlinePlus notes that some men may appear angry or irritable rather than sad. For easily missed signs, see 12 signs of depression people often ignore.

Why does knowing what causes depression matter?

Understanding what causes depression for you matters because it shapes the treatment plan and helps you let go of self-blame. NIMH notes that medications taken for an illness can cause side effects that contribute to depression symptoms, so a cause like that may be addressed by working with the prescribing doctor.

Here is how causes can guide care, offered as general examples only:

• If an untreated thyroid problem is contributing, treating it may help mood.
• If heavy drinking is involved, treatment usually addresses both alcohol use and mood together.
• If a recent loss or trauma is central, therapy may focus on grief or trauma processing.
• If depression runs in your family or keeps returning, a longer-term plan to prevent relapse may make sense.

Often, you will never pin down a single reason, and that is fine. What causes depression is less important day to day than what helps you recover, and treatment can work even when the cause is unclear.

How is depression diagnosed?

Depression is diagnosed through a conversation with a health professional about your symptoms, history and daily functioning, sometimes alongside a questionnaire and medical tests. There is no single blood test for depression, but a doctor may order labs to rule out other conditions. MedlinePlus notes that hypothyroidism is diagnosed with thyroid blood tests.

Expect questions about how long symptoms have lasted, sleep, appetite, energy, substance use, family history, medical conditions and medications. A clinician will also ask about safety. If you have already had a positive screening, read what to do after a positive depression screen.

What are the treatment options for depression?

Depression treatment usually involves psychotherapy, medication or both, matched to your symptoms and preferences. NIMH notes that evidence-based therapies to treat depression include cognitive behavioral therapy and interpersonal therapy, and that brain stimulation therapy is an option when other treatments have not worked.

• Psychotherapy: helps you change unhelpful thinking and behavior patterns, solve problems and improve relationships.
• Medication: antidepressants are commonly used. MedlinePlus notes they may take four to eight weeks to work, and you should not stop taking them on your own.
• Lifestyle supports: regular sleep, movement, daylight and social contact support recovery but do not replace treatment for moderate or severe depression.

Every medication can have side effects, and finding the right one may take trial and error. Questions about a specific medicine belong with your prescriber. For how therapy works, see how therapy helps depression.

Step by step: what should I do if I think I have depression?

If you think you have depression, start by tracking symptoms and booking an evaluation rather than waiting for it to pass. NIMH notes that most people with depression benefit from mental health treatment. These steps can make the process easier.

1. Write down your main symptoms and when they started.
2. Note how they affect work, school, relationships and self-care.
3. List all medications, supplements, alcohol and other substance use.
4. Book a visit with a primary care provider, therapist or psychiatric clinician.
5. Ask whether lab tests are needed to rule out medical causes.
6. Discuss treatment options and agree on a plan and a follow-up date.
7. Tell one trusted person what is going on.

What should I tell a clinician?

Tell a clinician what you have been feeling, for how long, and how it affects your days, including anything that feels hard to say. A short checklist helps:

• "I have felt low or numb most days for about ___ weeks."
• "I have lost interest in ___."
• "My sleep, appetite or energy has changed in these ways: ___."
• "Depression runs in my family," if it does.
• "I take these medications and supplements: ___."
• "I have had thoughts of not wanting to be alive," if you have.

MedlinePlus notes that certain medicines can cause symptoms like depression, which is why your full medication list matters.

Being honest about suicidal thoughts helps your clinician keep you safe. It does not automatically mean hospitalization.

When should I get help sooner?

Get help right away if you have thoughts of suicide or self-harm, cannot care for yourself, or have symptoms such as hearing voices. NIMH notes that depression symptoms can include thoughts of death or suicide or suicide attempts, which always need prompt attention.

• Thoughts of suicide, a plan or giving away possessions.
• Not eating or drinking enough for days.
• Hallucinations or beliefs that others say are not real.
• Rapidly worsening mood after starting or changing a medication.
• Unusually high energy, little need for sleep and risky behavior, which may signal bipolar disorder.

What should Texans know about depression care?

Texans can access depression care in person or by telehealth, and both can work well. A September 2024 research recap from the U.S. Department of Health and Human Services (HHS) found no significant differences in quality between remote and in-person care for conditions including depression.

NIMH notes that seasonal affective disorder is less common in places like Texas or Florida than farther north, so low mood in a Texas winter deserves a full evaluation rather than an assumption that it is seasonal.

Getting support in Texas

Lyte Psychiatry offers therapy, psychiatric evaluation and medication management in Texas. Lyte Psychiatry offers telehealth visits to patients who are physically located in Texas at the time of the visit, and in-person visits are available at its clinic in Pantego, in the Dallas–Fort Worth area. Most new patients are seen within 1–2 business days. Weekend appointments are limited. All Lyte Psychiatry services are available in Spanish.

Availability, insurance and clinician fit require confirmation. Learn about depression care or medication management.

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.