Types of Depression: What You Should Know

Depression can present itself in several ways. It can be mild or severe, and it can be short-lived or chronic. Special circumstances, like the birth of a baby or the changing of the seasons, can trigger depressive symptoms.
Understanding the type of depression a person is experiencing helps healthcare providers determine treatment. And for people who are diagnosed with depression, having information about their specific disorder can be beneficial.
"Folks seem comforted in knowing what's going on for them," said Sarah Noble, DO, a psychiatrist with the Einstein Healthcare Network in Philadelphia. "At least they have an answer for why they're experiencing what they're experiencing." Here's what you should know about the different types of depression.
Major Depressive Disorder
In 2020, approximately 21 million American adults had experienced at least one major depressive episode, according to the National Institute of Mental Health (NIHM). Under diagnostic criteria published by the American Psychiatric Association, people must have at least five symptoms persisting for two weeks or longer to be diagnosed with major depressive disorder. Those symptoms can include:
Feelings of sadness, emptiness, worthlessness, hopelessness, and guilt
Loss of energy, appetite, or interest in enjoyable activities
Sleep habit changes
Thoughts of death and suicide
Major depressive disorder has two subtypes: "atypical depression" and "melancholic depression." People who fall into the former category tend to sleep and eat a lot. They are emotionally reactive and very anxious, Dr. Noble explained. Those in the latter category have trouble sleeping and tend to ruminate over guilt-ridden thoughts, Dr. Noble added. Young adults tend to present with atypical depression, and the melancholic type is seen more often in older adults.
Most cases are highly treatable and may consist of pharmacological options, therapy, or lifestyle changes per the National Library of Medicine (NLM). However, individuals with major depressive disorder may begin with psychotherapy and medications as their treatment.
Treatment-Resistant Depression
Sometimes people with major depressive disorder don't readily respond to treatment—their depression stubbornly hangs on. "Maybe it's genetic, maybe it's environmental," Dr. Noble said. "Their depression is just tenacious." According to researchers of a January 2020 Neuropsychiatric Disease and Treatment study, for a person to be diagnosed with treatment-resistant depression, they need to have gone through two unsuccessful pharmacotherapy trials.
Helping people overcome treatment-resistant depression begins with a thorough workup to ensure a proper diagnosis and identify other psychiatric and medical causes of their symptoms. Patients are counseled on proper dosage and duration of treatment. If a medicine isn't working, healthcare providers will try switching to a similar drug or one from a different class. Patients may benefit from adding a second antidepressant from a different class and perhaps another type of medicine, such as an antipsychotic.
Subsyndromal Depression
A person who has depressive symptoms but doesn't quite check all the boxes for a diagnosis of major depression may be deemed "subsyndromal"—have an other specified depressive disorder, as indicated by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). For example, the person might have less than five symptoms or experienced depression for less than the two-week minimum.
"Rather than look at symptoms, I usually look at functionality," Dr. Noble added. Is the patient able to go to work and take care of day-to-day responsibilities? If the person is struggling, they may still benefit from treatment, including with medication, Dr. Noble said.
Persistent Depressive Disorder
People with persistent depressive disorder (PDD)—formely known as dysthymia—have "a low, dark, or sad mood on most days" and at least two additional symptoms of depression lasting two years or more per MedlinePlus. In children and teens, PDD may be diagnosed if symptoms of irritability or depression persist for a year or more. "It may wax and wane in intensity, but generally it's a low level of depression," Dr. Noble explained.
To be diagnosed with this type of depression, people must also have two of the following:
Sleep problems (too much or too little)
Low energy or fatigue
Low self-esteem
Poor appetite or overeating
Poor concentration or difficulty making decisions
Feelings of hopelessness
Usually PDD requires treatment with a combination of medication and psychotherapy.
Premenstrual Dysphoric Disorder
Up to 10% of women of childbearing age experience premenstrual dysphoric disorder (PMDD). This severe form of PMS can trigger depression, sadness, anxiety, or irritability, as well as other extreme symptoms, in the week before a woman's period.
"It can be really uncomfortable, disabling, and interfere with a woman's day-to-day life," said Dorothy Sit, MD, associate professor of psychiatry and behavioral sciences at Northwestern University's Feinberg School of Medicine in Chicago.
Scientists believe these women may have an abnormal sensitivity to hormonal changes during their menstrual cycle. Taking antidepressants, specifically selective serotonin reuptake inhibitors (SSRIs), in the two weeks before their period or throughout the month can be very effective, Dr. Sit said. Certain types of contraception and pain relievers may help with symptoms too.
Depression Due to Bipolar Disorder
Wide swings in mood and energy, from elation to hopelessness, are the signatures of depressive episodes in bipolar disorder. To be diagnosed with this form of depression, a person must have experienced at least one bout of mania (a period of time with energetic behavior).