Persistent depressive disorder (dysthymia)

Dysthymia describes a long-term low mood that becomes so familiar it can feel like simply "who I am." People with persistent depressive disorder may keep working, parenting and meeting obligations, yet carry a constant heaviness: less joy, less energy and a pessimistic outlook that rarely lifts for long.

The term dysthymic disorder was used for many years. Current diagnostic manuals combine it with chronic major depression under the name persistent depressive disorder, or PDD. Clinicians look for depressed mood on more days than not for at least two years in adults, along with other symptoms, without long breaks of feeling well.

Because the onset is often gradual and may begin in adolescence or early adulthood, many people don't realize that their low-grade depression is a treatable condition. Some only seek help when a more severe depressive episode develops on top of the chronic low mood, sometimes called "double depression." Recognizing dysthymia earlier can make a real difference to quality of life.

The core symptom is a depressed or low mood on most days. In children and teenagers, this can look more like irritability. It's usually accompanied by at least two of the following:

• Poor appetite or overeating
• Sleeping too little or too much
• Low energy or constant tiredness
• Low self-esteem or harsh self-criticism
• Trouble concentrating or making decisions
• Feelings of hopelessness

People also often describe a sense that life is gray or flat, difficulty enjoying things they used to like, social withdrawal, feeling like a burden and a tendency to expect the worst. Some notice emotional numbness rather than sadness.

What sets dysthymia apart is duration. Symptoms may wax and wane, but the person rarely has more than a couple of months feeling truly well. Others may see them as gloomy or low-energy without recognizing a health condition. If this description feels familiar and has been true for years, it's worth discussing with a licensed professional.

Persistent depressive disorder has no single cause. Several factors usually combine:

• Family history. Depression, including chronic depression, tends to run in families, suggesting a genetic contribution.
• Early adversity. Childhood neglect, abuse, loss of a parent or a chronically stressful home environment are associated with a higher risk.
• Ongoing stress. Long-term financial difficulty, relationship problems, isolation or caregiving can sustain low mood.
• Personality and thinking style. A tendency toward self-criticism, pessimism or low self-esteem can both contribute to and result from long-term low mood.
• Health factors. Chronic illness, chronic pain, sleep problems and some medications can play a role, as can substance use.
• Other conditions. Anxiety disorders, ADHD and personality difficulties frequently occur alongside PDD.

None of these factors means a person is destined to have dysthymia, and having it is not a character flaw. Understanding the contributors in your own life helps a therapist tailor treatment.

Major depression involves more intense symptoms lasting at least two weeks, often with a clear episode that begins and ends. Dysthymia is typically milder in intensity but much longer lasting. The two can overlap, and a person with PDD can experience major depressive episodes too.

High-functioning depression is not a formal diagnosis, but people often use it to describe being outwardly successful while privately struggling. Many people who identify with the phrase are describing something close to dysthymia.

Emotional numbness and low self-esteem are common features of chronic depression rather than separate conditions, though they can also appear in other contexts such as trauma.

It's also important to distinguish dysthymia from the low periods of bipolar disorder, and from mood changes caused by thyroid problems or other medical issues. A thorough assessment by a licensed mental health professional, sometimes alongside a medical checkup, helps clarify the picture and guide treatment.

Chronic depression often takes a little longer to treat than a single depressive episode, but there are effective options.

Psychotherapy is central. Cognitive behavioral therapy (CBT) helps people identify and change the long-standing negative beliefs and habits that keep low mood going. Behavioral activation focuses on gradually reintroducing rewarding activities. Interpersonal therapy addresses relationship patterns and life transitions. Some therapists use approaches developed specifically for chronic depression that focus on how thoughts and behaviors affect interactions with others.

Medication may be recommended by a psychiatrist or other prescribing clinician, sometimes in combination with therapy. Research suggests that combining the two can be particularly helpful for chronic depression. A prescriber will discuss benefits, side effects and how long to continue.

Lifestyle supports such as regular sleep, physical activity, social contact and reducing alcohol use complement professional treatment.

Because dysthymia has often been present for years, change may be gradual. Many people describe the experience as slowly discovering what it feels like to feel well.

A clinical psychologist or licensed psychologist can assess persistent depressive disorder and provide evidence-based therapy. A psychiatrist can evaluate whether medication might help and manage it over time. Your primary care doctor can also be a starting point and may check for medical causes.

In a first appointment, expect questions about how long your mood has been low, how it affects your work and relationships, your sleep, appetite and energy, any history of depression in your family, and whether you've ever had thoughts of self-harm. Questionnaires are common. It's fine to say "I've always been like this" — that's useful information.

Consider seeking help if low mood has lasted for years, you can't remember the last time you felt genuinely well, or it is limiting your life. Seek urgent help if you have thoughts of suicide: call 911 or your local emergency number, or call or text 988 in the US (Samaritans 116 123 in the UK and Ireland).

Meanwhile, small steps help: keep a routine, schedule one enjoyable activity each day and stay connected with at least one person.