A major depressive episode, which is characterized by a depressed mood that lasts most days for at least 2 weeks, may come with the following symptoms:
- Persistent sadness and hopelessness
- Difficulty concentrating and remembering things
- Loss of interest in hobbies and activities
- Changes in sleep patterns (either too little or too much sleep)
- Fatigue or loss of energy nearly every day
- Changes in appetite (either increased or decreased appetite), leading to weight changes
- Restlessness or feeling slow
- Feeling excessive worthlessness or guilt
- Suicidal thoughts 1
In the United States, over 20 million adults have experienced depression at some point, according to data from 2020. 2 When left unaddressed, this mood disorder can greatly impact day-to-day life, including the ability to complete work obligations or maintain social relationships.
Although many people suffer from clinical depression, the cause isn't always clear. Researchers suggest that genetics, hormones, environment, brain chemistry and other factors play a role in the development of depression. 3 It's worth noting that there are different types of depression, each of which has its own cause.
Types of Depression
Major depressive episodes aren't the only type of depression a person can experience. Other forms of depression include the following.
- Persistent depressive disorder (PDD): PDD is a mild to moderate form of chronic depression. It occurs when someone experiences depression for over 2 years. 4
- Postpartum depression (PPD): As the name suggests, this type of depression impacts women after pregnancy. 5
- Seasonal affective disorder (SAD): This is a temporary form of depression associated with seasonal changes. Typically, it arises during the winter. 6
- Bipolar disorder: Formerly called manic depression, this disorder causes sudden mood changes. 7
- Psychotic depression: Put simply, psychotic depression is a form of clinical depression that comes with psychotic features like hallucinations and delusions. 8 Psychotic depression is also common among the elderly.
- Premenstrual dysphoric disorder (PMDD): PMDD is connected to a woman's menstrual cycle. It causes depression and increased irritability. 9
In 2017, over 264 million people across the globe experienced some form of depression. 10 Considering they're all classified as types of depression, these conditions share many similarities. For example, they each cause symptoms like sadness, hopelessness, and loss of interest in previously enjoyable activities. However, they also have some key differences. To better understand these differences, here's a closer look at a few of the most prevalent depression types.
What Is Major Depression?
Major depression, also called major depressive disorder (MDD) and clinical depression, is one of the most common forms of depression. As mentioned earlier, it impacts over 20 million Americans and is characterized by a consistently poor mood that occurs nearly every day for 2 weeks and interferes with day-to-day life. If it continues for over 2 years and the symptoms are mild to moderate, it becomes persistent depressive disorder.
For diagnosis, must experience at least five out of nine symptoms listed in the diagnostic criteria for a major depressive episode. There are many factors that can increase a person's risk factors of MDD, including substance use, a negative environment, and having a family history of depression. 11
What Is Postpartum Depression?
After giving birth, it's common for women to feel sad, hopeless, or overwhelmed. Many women also have difficulty sleeping or experience episodes of intense crying. These emotions and behaviors are known as "the baby blues" and generally fade after a few days. If they last for more than 2 weeks, it's called postpartum depression (PDD). Women with PDD typically experience the following:
- Empty, sad emotions
- Sadness that impacts day-to-day life
- Feeling disconnected from their child 12
PDD is a fairly common condition that impacts about one in seven women. 13 Although it can affect any new mother, it's more common among women who have a family history of depression, experience a lack of familial support, or have struggled with depression during their pregnancy. 14
What Is Seasonal Depression?
Seasonal depression, or seasonal affective disorder (SAD), is a form of depression that's directly connected to the seasons. For most people, SAD begins during autumn, continues throughout the winter, and resolves around springtime. In addition to causing common major depression symptoms, SAD may result in the following:
- Weight gain and cravings for carbohydrates
- Persistent low energy 15
SAD affects up to 3% of the general population and up to 20% of MDD patients. 16 While the cause isn't certain, research suggests it may be connected to the lack of sunlight in the winter. Reduced sunlight is associated with lower levels of serotonin (a brain chemical that impacts mood), as well as lower levels of vitamin D. 17
How to Know If You Have Depression
Unlike most physical medical conditions, depression cannot be diagnosed through blood or laboratory work. The best way to determine if someone has depression is by analyzing symptoms. Anyone who notices persistent sadness that affects day-to-day life should speak with their doctor.
During a consultation, doctors will ask about symptoms. They may also inquire about risk factors, such as family history or substance use. If they suspect depression, the next step is treatment. 18
How to Treat Depression
Treatment for depression varies depending on the cause. Oftentimes, doctors recommend a combination of antidepressants and talk therapy.
Antidepressants are a type of medication that impacts brain chemicals known to influence mood. In many cases, antidepressants have a positive effect on depression symptoms — in one study, between 40% and 60% of patients who took them noticed an improvement in mood within 8 weeks. 19
Along with medication, many doctors recommend psychotherapy (or talk therapy). One of the most common depression treatments is cognitive-behavioral therapy. During these sessions, patients work with counselors to transform negative thought patterns into positive ones. 20
How to Deal With Depression
Being diagnosed with depression isn't easy. Many people feel guilty or ashamed about their emotions, which causes them to try and hide their depression. 21 Over 50% of people with a mental illness do not seek treatment. 22 Unfortunately, withdrawing from others can actually worsen symptoms and increase negative thoughts.
Whether someone has temporary SAD or long-lasting PDD, it's essential to seek the support of loved ones and speak to a doctor about symptoms. Many individuals with depression patients eventually experience symptom relief after starting treatment. 23 To learn more, visit How to Find Help Treating a Depressive Disorder.