What causes depression? Diagnosis, prevention, and treatment

Overview: What is depression?

Everyone feels down or bummed out from time to time. However, prolonged feelings of sadness that lead to a lack of energy, loss of interest in previously enjoyed activities, or even thoughts of death can be the telltale signs of depression. 

Knowing the causes of depression can be helpful if you want to prevent future symptoms and episodes. Depression can be severe if not diagnosed and treated, so awareness of the relevant risk factors is important. 

What causes depression?

There are many causes of depression. Some may vary based on family history, age, sex, environment, medication history, or lifestyle. To better understand these, the following lists consist of the most common general and demographic-specific causes of depression. 

General causes: 

• Abuse or other forms of traumatic events

• Personal conflicts with friends or family

• Major life events, both positive and negative

• Death or loss

• Family history of depression

• Substance abuse issues

Old age-related causes: 

• Medical conditions 

• Caregiver stress

• Difficulty sleeping

• Loneliness 

• Physical limitations and lack of exercise 

• Substance and medication-related problems

Illnesses and medical disorders that could cause depression:

• Thyroid disease 

• Chronic illnesses or pain

• Heart disease 

• Diabetes 

• Brain-related diseases

• Pre-existing mood disorders

Medications that could cause depression: 

• Acne treatment medication, such as isotretinoin 

• Anticonvulsants, such as Zarontin (ethosuximide) or Celontin (methsuximide)

• Barbiturates, such as phenobarbital

• Benzodiazepines, such as Xanax (alprazolam), Ativan (lorazepam), or Klonopin (clonazepam)

• Opioids, such as Demerol (meperidine) or OxyContin (oxycodone) 

• Smoking deterrents, such as varenicline

Lifestyle factors that could cause depression: 

• Overworking

• Stress from work, school, and interpersonal relationships 

• Difficulty sleeping or bad sleeping habits

• Poor diet decisions

• Sedentary lifestyle or lack of exercise 

Additionally, women are nearly twice as likely as men to have depression. Additional biological factors may cause depression in women, including: 

• Premenstrual syndrome-related issues 

• Pregnancy 

• Postpartum depression

• Menopause

• Real-life situations involving gender discrimination and inequality

Risk factors for depression

Depression can be difficult to prevent. However, it is important to know the relevant risks of depression when considering treatment methods. These include:

• Genetic depression: The hereditary factor of depression is very complex. A 2021 study found 178 gene variants linked to depression, but researchers believe there could be even more to discover.

• Existing medical conditions: Illnesses or other medical problems that disturb the body’s chemical balance may cause depression. Medical researchers identify stroke and heart disease as two severe medical issues linked to depression or depressive symptoms in patients. Depressive symptoms are commonly seen in people with chronic pain, fatigue, cancer, or diabetes. 

• Recent or early life trauma: Negative life events and the trauma following them can cause depression and other mental disorders. 

• Environmental factors: Extenuating circumstances that affect daily life, such as unemployment, poverty, abuse, or neglect, can be overwhelming and put a person at risk of developing depressive symptoms. Other mental disorders, such as anxiety, may also form and worsen depressive symptoms. 

• Postpartum depression: According to the American Pregnancy Association, about 70% to 80% of women will experience the “baby blues” after childbirth, while 10% to 20% will experience postpartum depression.

Is depression serious? When to see a doctor

Depression can vary in severity. Some report low-grade symptoms that last for a short period, while others may experience worsening symptoms over longer periods. Awareness of the risk factors that may cause depression, especially if they apply to you, is important. Although it is difficult to prevent depression, preparing for and delaying depressive symptoms is doable.

If depression occurs daily for at least two weeks, make an appointment with a healthcare provider as soon as possible. Do not endure prolonged periods of depression alone or without help if symptoms worsen. Significant changes to your daily schedule, sudden weight loss, and disruptions to your sleep are a few of depression’s more dangerous effects. At worst, it can lead to self-harm and thoughts of death. 

There are different types of depression, such as bipolar disorder, seasonal affective disorder, and major depressive disorder, that are more serious and require more involved treatment. Longer depressive episodes with the addition of unfamiliar symptoms may indicate a more severe issue. 

Primary care providers and mental health professionals, such as psychiatrists, psychologists, or social workers, can help diagnose and provide effective treatment for depression. 

If your symptoms disappear after the first episode, do not discount the possibility of their return. A 2018 study found that people with at least one episode will have another sometime in their life. It may be worth your time to seek a diagnosis and treatment, even if you experience depression only once. 

How is depression diagnosed?

A healthcare provider may diagnose depression after conducting a screening. These involve asking patients about their symptoms, mood, and other relevant topics. Even though it may lead to a diagnosis, screening may not always be effective. Symptoms may not be as observable or severe during the screening as they are on other days, which could result in a lack of diagnosis. This isn’t always the case, but keep it in mind. 

A few of these screening methods may include: 

• Beck Depression Inventory: This consists of 21 questions about symptoms. Respondents give a score of zero to three for each question, with higher scores indicating more severe depression. 

• Hamilton Depression Rating Scale (HDRS): There are multiple versions of the HDRS, but scoring is based on 17 questions that are typically used to assess the severity of a diagnosis. 

• Patient Health Questionnaire (PHQ-9) This test consists of nine questions about symptom occurrence, scored from zero to three based on their frequency. 

• Zung Self-Rating Depression Scale (SDS): This consists of 20 questions about symptoms, ranked from one to four. The score range is from 20 to 80. Any score over 69 is considered a major depressive disorder. 

A healthcare provider uses the answers to these questionnaires to determine the severity and type of depression you may have. A healthcare provider must observe five or more symptoms of depression present for two weeks in order to make a diagnosis. These symptoms can be found in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the standard resource on mental health disorders. Outside of a low mood, these symptoms include: 

• Appetite or weight changes 

• Abnormal sleeping habits 

• Restlessness and agitation

• Fatigue

• Trouble focusing

• Guilt, despair, or feelings of worthlessness

• Suicidal thoughts and ideation 

A healthcare provider may administer a blood test or other laboratory test to screen for additional causes of depression symptoms, such as other illnesses and disorders. Be sure to disclose any current medications if your healthcare provider prescribes an antidepressant upon diagnosis. 

Is depression hereditary? 

Depression is not guaranteed to be a hereditary disorder, but genetics can increase a person’s likelihood of experiencing depressive symptoms at some point throughout life. If a loved one has experienced depression or other mental health conditions, contact your healthcare provider. 

Is depression curable?

There is no definitive cure for depression. However, many treatment options are available to make symptoms more bearable. 

Psychological treatment commonly involves discussing your mood or behavior with a mental health professional. These may include: 

• Cognitive behavioral therapy (CBT): Seeks to help patients identify and learn from negative thoughts and behaviors 

• Interpersonal therapy: Seeks to help patients improve relationships with friends, family members, and others 

• Talk therapy (psychotherapy): A more general therapy aimed at the patient’s needs

Increasing awareness of your thoughts and actions can help you better understand what may trigger depression and its symptoms. This can help improve your ability to identify negative patterns of behavior that may make your depression worse. Like any type of treatment, psychological treatment can last however long it is necessary. Your healthcare provider can help track your progress, but it’s also important to recognize its effects on your everyday life. 

Antidepressants are meant to relieve symptoms of depression. Depending on the depression diagnosis, a healthcare provider may prescribe a specific antidepressant medication. These increase neurotransmitters in the brain, such as serotonin, norepinephrine, and dopamine, in order to improve a person’s mood. These include: 

• Selective serotonin reuptake inhibitors (SSRIs): These are the most widely used type of antidepressant, which include Prozac (fluoxetine), Zoloft (sertraline), and Paxil (paroxetine). They increase the levels of serotonin in the brain.

• Serotonin and norepinephrine reuptake inhibitors (SNRIs): These increase the levels of serotonin and norepinephrine in the brain and include Effexor XR (venlafaxine ER), Pristiq (desvenlafaxine), and Cymbalta (duloxetine). 

• Serotonin modulators: These increase levels of serotonin in the brain by stimulating and blocking serotonin receptors. They include Serzone (nefazodone), Desyrel (trazodone), and Viibryd (vilazodone). 

RELATED: Medications that treat anxiety and depression

Like psychological treatment, medication treatment does not necessarily have a fixed timeline. It may take as little as a week to as much as eight weeks to see the effects of antidepressants. Finding the right medication for you may also take time. This is perfectly normal. Keep your healthcare provider informed about any adverse side effects or issues. 

Sometimes, a healthcare provider may recommend electroconvulsive therapy (ECT) as a treatment for depression. ECT is performed in cases of severe depression and other mental health problems resistant to treatment. It passes electrical currents through the brain to trigger a brief seizure, which can alter a patient’s brain chemistry enough to reverse depressive symptoms. Despite how it sounds, ECT is a safe procedure. 

How to prevent depression

Preventing depression is possible, but know that it may not stop symptoms or episodes. Adjusting your daily routine and learning how to manage stress levels can help increase your likelihood of preventing depression. 

First, there are lifestyle changes known to help fight depressive episodes. These include: 

• Exercising: Regular exercise is considered to be one of the best ways to improve overall well-being and prevent depression. It can boost mood by releasing endorphins, improve brain function over time, and strengthen your immune system. Lower-intensity, consistent physical activity is recommended over infrequent high-intensity exercise, so find a plan that works for you. 

• A healthy diet: The right nutrients can impact your mind. Studies have shown that improving your diet can help improve your depressive symptoms. Foods with fatty acids, such as fish, nuts, or kale, can be easily incorporated into a diet in creative and delicious ways. 

• Limiting your time on social media: Though this can include any online practice that results in strain, cutting back on social media shares a positive link with decreasing depression. Your usual time spent scrolling can be used instead to get outside and exercise or connect with friends in real life. 

• Strengthen connections with friends and family: There is a strong link between positive family relationships and mental health. For many, negative interpersonal relationships may be part of the cause of depression or anxiety. Focusing energy into spending more time with friends and family can be helpful. 

These prevention tips can help, but remember that they may not stop depression episodes from happening. Reviewing treatment options, the likelihood of developing depression, and any vulnerabilities to other potential causes or risk factors of depression are some of the best measures to prevent symptoms and future episodes. 

FAQs about depression causes

What does depression feel like? 

Although it’s known as a mental disorder, depression can take both a mental and physical toll on those who have it. Mentally, depression can feel like a prolonged state of joylessness or helplessness that poses barriers to a person’s concentration, motivation, and emotional regulation. Physically, depression may make sleeping difficult, leading to decreased energy and fatigue. 

What are the signs of depression?

Signs of depression can include loss of interest in previously enjoyed activities, fatigue, difficulty sleeping, uncontrollable emotions, inexplicable feelings of grief, or thoughts of suicide and death. 

How long does postpartum depression last?

Postpartum depression usually shows up within 2-3 days after delivery and, if untreated, may last months. Unfortunately, there is no average amount of time that postpartum depression lasts, so how long it may affect a person varies, even with treatment. 

What’s next? Additional resources for people with depression

Test and diagnostics

• What to expect from a depression screening, SingleCare

• Diagnostic and statistical manual of mental disorders, American Psychiatric Association

Treatments

• Medications that treat anxiety and depression, SingleCare

• Depression treatments and medications, SingleCare

• Paxil vs. Zoloft: Differences, similarities, and which is better for you, SingleCare

• How long does it take antidepressants to work?, SingleCare

Scientific studies and clinical trials

• Depression and associated physical diseases and symptoms, Dialogues in Clinical Neuroscience

• Gender differences in depression in representative national samples, American Psychological Association

More information on related health conditions

• Anxiety vs. depression: Compare causes, symptoms, treatments & more, SingleCare

• Are depression and heart disease connected?, SingleCare

• SAMHSA National Helpline, SAMHSA

• 988 Suicide & Crisis Lifeline

• Depression, National Institute of Mental Health