Caution: This fact sheet provides a general overview of Bipolar I and Bipolar II disorders based on the DSM-5 (Fifth Edition of the Diagnostic and Statistical Manual of Mental Disorders). It is not intended for diagnostic purposes. Only a licensed mental health professional can diagnose or provide personalized treatment.
Brief Description
Persistent Depressive Disorder (PDD) is a chronic form of depression in which a low mood persists for at least 2 years in adults and 1 year in children or adolescents. It is generally less severe than major depression but can significantly impact daily life and functioning.
Before 2013, this condition was known as Dysthymic Disorder (Dysthymia). In 2013, the DSM-5 combined dysthymia and chronic major depression into a single diagnosis called Persistent Depressive Disorder (PDD). This change reflected research showing that both conditions represent the same long-lasting form of depression.
Research indicates that approximately 70–80% of individuals with PDD experience at least one episode of major depression during their lifetime. This phenomenon is often referred to as “double depression,” where a major depressive episode occurs on top of the chronic low mood associated with PDD.
Difference Between Persistent Depressive Disorder (PDD) and Major Depression (MDD)
| Persistent Depressive Disorder (PDD) | Major Depressive Disorder (MDD) | |
| Duration | Lasts at least 2 years in adults (1 year in children/adolescents) | Shorter episodes, usually ≥2 weeks but can last months |
| Severity | Generally milder, low-level chronic symptoms | Usually more severe, intense sadness and functional impairment |
| Course | Continuous, symptoms rarely fully go away | Episodic, periods of normal mood between episodes |
| Onset | Often begins in childhood, adolescence, or early adulthood | Can begin at any age, often triggered by stress or biological changes |
Course
- Chronic: symptoms last 2 years or more without full remission
- May fluctuate in intensity, sometimes overlapping with major depressive episodes (“double depression”)
Causes & Risk Factors
- Genetic factors: family history of depression or mood disorders
- Neurobiological factors: changes in serotonin or other neurotransmitter systems
- Environmental stressors: chronic stress, trauma, abuse, or neglect
- Personality factors: being more easily upset or having a harder time coping with stress
- Other mental/physical health conditions: anxiety disorders, chronic illness
Diagnostic Criteria (DSM-5)
- Depressed mood most of the day, for ≥2 years (≥1 year in children/adolescents)
- Presence of ≥2 of the following:
- Poor appetite or overeating
- Insomnia or hypersomnia
- Low energy or fatigue
- Low self-esteem
- Poor concentration or difficulty making decisions
- Feelings of hopelessness
- Never symptom-free for >2 months during the 2-year period
- Symptoms cause significant distress or impairment
- Not better explained by another mental or medical condition
Treatment Options
- Psychotherapy: Cognitive Behavioral Therapy (CBT), interpersonal therapy, or psychodynamic therapy
- Medications: Antidepressants (SSRIs, SNRIs, tricyclics)
- Lifestyle approaches: Regular exercise, sleep hygiene, healthy nutrition, structured daily activities
- Combined treatment: Therapy + medication is often most effective
- Addressing co-occurring conditions: such as anxiety or substance use
What It Feels Like
- A constant low-level sadness or emptiness (“like a gray cloud you can’t shake”)
- Feeling tired or unmotivated most days
- Low self-esteem and hopelessness about the future
- Difficulty enjoying positive events or relationships
- Life feels “meh” rather than dramatically sad
Important Facts
- About 3–6% of the population experiences PDD at some point
- Can be mistaken for personality traits or chronic stress rather than a treatable disorder
- Support networks, therapy, and medication can significantly reduce symptoms
- Many people experience PDD for 5–10 years or more if untreated, and for some it can feel lifelong
- Co-occurring conditions:
- Roughly 25–50% of individuals with PDD also have an anxiety disorder
- Around 15–30% develop a substance use disorder
- Estimates vary, but 10–25% may have co-occurring personality disorders
Resources and Citations
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed., American Psychiatric Publishing, 2013.
Depression and Bipolar Support Alliance. DBSA. https://www.dbsa.org. Accessed 4 Sept. 2025.
Mental Health America. Mental Health America. https://www.mhanational.org. Accessed 4 Sept. 2025.
National Institute of Mental Health. NIMH. https://www.nimh.nih.gov. Accessed 4 Sept. 2025.
National Alliance on Mental Illness. NAMI. https://www.nami.org. Accessed 4 Sept. 2025.
SAMHSA. “SAMHSA Helpline: 1-800-662-HELP (4357).” Substance Abuse and Mental Health Services Administration, https://www.samhsa.gov/find-help/national-helpline. Accessed 4 Sept.
