Clinically reviewed by Dr. Chris Mosunic, PhD, RD, CDCES, MBA

What is depression? 

By Vivian Nunez

A look at the different clinical definitions of depressive disorders

Do you know how depression is defined? No, really. People often throw around the phrase “I’m depressed” to describe many different feelings or moments in time. But clinical depression or depressive disorders have specific characteristics. 

According to the National Institute of Mental Health, one of the key qualifiers to being diagnosed with depression is to have a combination of persistent symptoms for at least two weeks. Those depressive disorder symptoms can include experiences like feeling empty, hopeless, or worthless, or more physical cues like having noticeably less energy, difficulty concentrating, or changes in appetite. 

Therapists and mental health professionals use the DSM-5 (Diagnostic and Statistical Manual of Mental Health) to diagnose depression. The DSM-5 was last updated in 2013, and while it still stands as the go-to diagnostic tool, people’s lived experiences with depression have also added more context into how expansive symptoms like “loss of interest or pleasure in everyday activities” can actually manifest. 

For instance, while not specifically noted in the DSM-5, many people find that their feelings of emptiness can also be paired with a lack of motivation to shower or brush their teeth. 

On the Calm Health app, mental health screenings include questions from the Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) surveys. Both popular screening tools in the field of mental health are used to assess the severity of symptoms related to depression and generalized anxiety disorder, respectively. 

No matter how unique symptoms may present, depression affects about 16 million adults every year, according to the CDC. In 2020, the National Institute of Mental Health found that 4.1 million adolescents (between the ages of 12-18) had at least one depressive episode. 

What causes depression? 

There are different kinds of depression (more on this below), each with unique risk factors. Nonetheless, a lot of depressive conditions share similar baseline symptoms or causes. 

“Depression is one of the most common mental disorders in the United States,” writes the National Institute of Mental Health. “Research suggests that genetic, biological, environmental, and psychological factors play a role in depression.” 

Comorbidities (or other diseases) and even life experiences (like losing a loved one) can trigger a depressive episode. Depression is not caused by anything you did wrong. Just as NIMH writes, it’s a mental health disorder that can be triggered by so many factors that are outside your immediate control. 

What are the different kinds of depression? 

Because depression can be caused by everything from genetic factors to lived experiences, there are a few different conditions that fall under the “depression” umbrella. 

General Depression — This kind of depression can manifest as either major depression or persistent depressive disorder. Those who have major depression have been struggling with depressive symptoms for at least two weeks. On the other hand, those who have been struggling with consistent symptoms for at least two years are diagnosed by a medical provider with persistent depressive disorder. 

Premenstrual Dysphoric Disorder (PMDD) — PMDD can be caused by extreme hormone fluctuations or triggered by pre-existing mental health conditions. PMDD has overlapping symptoms with PMS (premenstrual syndrome), like mood changes, low energy, and food cravings. PMDD differs from PMS because its symptoms are more severe, persistent, and consistent cycle after cycle. According to the Office on Women’s Health, a person must have five or more PMDD symptoms to be diagnosed and treated for PMDD. 

Prenatal Depression — Depression related to pregnancy and childbirth is not limited to postpartum depression (or depression with onset after birth). Prenatal depression is a depressive episode that starts at any point during pregnancy. Those with prenatal depression struggle with feelings of emptiness, hopelessness, or inability to care for themselves or their pregnancy. 

Postpartum Depression — It’s normal and expected for women to feel a wave of emotions after giving birth. The “baby blues” define that two-week window after childbirth when a mom’s hormones are still settling, and she could feel plagued by sadness, exhaustion, or worry. According to the CDC, the main difference between the “baby blues” and postpartum depression is the intensity and duration of the symptoms. Postpartum depression is a depressive episode that extends beyond those first two weeks. 

Seasonal Affective Disorder (SAD) — There are two kinds of seasonal affective disorders — winter-pattern SAD and summer-pattern SAD. One is triggered by the darker, colder seasons, while the other is triggered by the warmer, brighter seasons. According to the National Institute of Mental Health, “SAD is not considered a separate disorder but is a type of depression characterized by its recurrent seasonal pattern, with symptoms lasting about 4 to 5 months per year.” It shares symptoms with General Depression, like difficulty enjoying everyday activities, fatigue, or mood changes. 

Depression with psychosis symptoms — Those who struggle with depression with psychosis symptoms are prone to having delusions (false beliefs) or hallucinations (hearing voices that are not there). According to the NIMH, those navigating psychosis are also prone to behavior or reactions that are not aligned with the situation at hand. Before a psychosis episode, people can develop behavioral symptoms like feeling overly (and newly) suspicious, difficulty telling reality from fantasy, or trouble taking care of themselves. 

Each person’s symptoms and triggers are unique. According to NAMI, someone struggling with depression may be treated with such things as medications, psychotherapy, light therapy, brain stimulation, and other techniques. 

While depression, no matter the type, is treated on a case-by-case basis, there are tools that can universally help. Calm’s module walks you through those and then some.  

Calm Health is a mental health wellness product. Calm Health is not intended to diagnose or treat depression, anxiety, or any other disease or condition. Calm Health is not a substitute for care by a physician or other health care provider. Any questions that you may have regarding the diagnosis, care, or treatment of a medical condition should be directed to your physician or health care provider.

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