Persistent Depressive Disorder (Dysthmyia)

The DSM-V spells out specific diagnostic criteria for PDD. For a diagnosis of PDD, adults must experience a depressed mood for at least two years, and symptoms cannot be absent for more than two months. Someone with PPD must also experience at least two of the following symptoms to meet the diagnostic criteria:

• Overeating or poor appetite
• Hypersomnia or insomnia
• Low self-esteem
• Poor concentration or decision making
• Thoughts of hopelessness

These symptoms must cause significant impairment and distress in critical areas of functioning, like at school, work, or socially. Children and adolescents can also have PDD, but their mood can be irritable instead of depressed, and they only need to experience the symptoms for one year instead of two. 

People with PDD are more likely to experience bouts of MDD, and it is possible to be diagnosed with PDD and MDD at the same time. This clarification is one of the significant differences between the DSM-IV and the DSM-V. The DSM-V states explicitly that someone can have a comorbid diagnosis of MDD and PDD, often referred to as “double depression.” 

Recent research shows that the prevalence of people with both PDD and MDD is 15.2%. After the episode of major depression ends, the person may experience PDD symptoms rather than being symptom-free. Some PDD and MDD symptoms overlap, but they are more severe with MDD. Some signs of a major depressive episode include: 

• Depressed mood most of the day, every day
• Diminished pleasure or interest in activities
• Weight changes
• Sleep changes
• Fatigue
• Thoughts of worthlessness or feelings of guilt and shame 
• Diminished ability to think or concentrate

There is no primary cause of PDD identified, but it may be due to a combination of factors, including prior mental illness, brain chemistry, genetics, stress, trauma,² and social circumstances. Some potential contributing factors of PDD include the following:

• Brain chemistry: The chemistry that controls mood in the brain is complex. Many theories about the causes of depression point to serotonin levels as a possible cause, but others have identified additional neurotransmitters, like epinephrine and dopamine, that may affect mood. 
• Brain structure: Brain changes may also contribute to depression, as some parts of the brain are significantly smaller in volume in people with depression.
• Childhood trauma: Recent research shows that childhood trauma is linked to chronic depression in adulthood. Some studies found that emotional and sexual abuse in childhood had a more significant association with dysthymia or PDD than depression.
• Genetics: PPD does seem to run in families, but scientists have not yet discovered any specific genes that cause this.

There is no cure for depressive disorders like PDD, but many types of treatment can help manage symptoms, such as therapy or medications like selective serotonin reuptake inhibitors (SSRIs). 

Medication

The first line of medication therapy for depression is a selective serotonin reuptake inhibitor (SSRIs) or other antidepressant. 

There are multiple types of antidepressants available, including selective serotonin reuptake inhibitors (SSRIs), selective serotonin noradrenaline reuptake inhibitors (SSNRIs), and atypical antidepressants. Finding the right medication can be a lengthy process with the guidance of a healthcare professional, and individuals may consider their symptoms, side effects, age, health, and any other medications before settling on a treatment plan. 

Consult a medical doctor before starting, changing, or stopping a medication for any condition, including selective serotonin reuptake inhibitors (SSRIs). The information in this article is not a replacement for medical advice or diagnosis. 

Self-care

Self-care is not a cure for depression, but recent research shows that engaging in self-care can improve mental health and reduce depression symptoms. Below are ways to get started: 

• Exercise regularly: Aim for 30 minutes of exercise a day. Even two 15-minute walks a day may help.
• Eat well: Eat regular, healthy meals and stay hydrated.
• Prioritize sleep: Stick to a regular sleep schedule and get seven to nine hours of sleep per night. 
• Relax: Make time for relaxing activities like breathing exercises, meditation, journaling, or yoga. 
• Practice gratitude: Remind yourself of all you have to be thankful for.
• Practice optimism: Stay positive by recognizing and challenging negative thoughts. 
• Stay connected: Stay connected to friends and family and reach out for support when needed.

Therapy is a standard treatment for PDD, and recent research shows that a treatment plan with both therapy and medication is more effective than either one on its own. There are many types of therapy available and options for finding available therapists. Online therapy may be a convenient choice for people with PDD because they can attend from the comfort of home and do not have to speak to someone face-to-face. Through a platform like BetterHelp, clients can choose between phone, video, and chat sessions with their therapist. 

The Anxiety and Depression Association of America (ADAA) has a multitude of resources available online, including anonymous peer-to-peer support communities where you can connect with people who are willing to share their own stories about living with depression. 

The National Institute of Mental Health offers valuable information on its website, including digital shareables to start a conversation about depression on social media.  

If you are experiencing suicidal thoughts or urges, call the 988 Suicide & Crisis Lifeline at 988 or text 988 to talk to a crisis provider over SMS. They are available 24/7 to offer support. 988 also provides an online chat for those with an internet connection. Please see our Get Help Now page for more immediate resources.

For those experiencing abuse, contact the Domestic Violence Hotline at 1-800-799-SAFE (7233). Support is available 24/7. Please also see our Get Help Now page for more immediate resources.

A 2020 study published in Frontiers in Psychology found that persistent depressive disorder is a significant risk factor for loneliness. Loneliness was associated with a lack of social support and a history of traumatic events in the study group, which also consisted of individuals with borderline personality disorder (BPD). The study authors suggest considering this finding when developing future treatments for PDD.

A study published in the Journal of Affective Disorders looked at whether the “Unified Protocol for Transdiagnostic Treatment of Emotional Disorders (UP)” would be effective in treating various depressive disorders, including PDD. UP is a modality based on cognitive-behavioral therapy that focuses on emotions and temperament. All study participants responded well to the intervention, with many upholding recovery in the 12-month follow-up appointment. This study showcases the potential for a new treatment for depression.

Below are several statistics about persistent depressive disorder:

• Depressive disorders, including PDD, have a prevalence of about 12% worldwide, but the prevalence is slightly higher in the United States, where it’s estimated that the prevalence of major depressive disorder is 17%. Contrarily, persistent depressive disorder has a 3% prevalence rate. 
• According to the National Alliance on Mental Illness, about 75% of people with PPD also experience at least one major depressive episode.
• Some recent research shows that people with dysthymia or PDD may improve slower than people who are non-chronically depressed. Results from a recent study found that, at a 10-year follow-up, 60% of people with PDD still met the criteria for depressive disorder, compared to only 21% of those with non-chronic disorders. 
• A recent meta-analysis found that therapy may be especially effective for mild to moderate depression. Those who received psychotherapy for depression had higher remission rates than those in control groups. CBT had the highest remission rate, at 66%.