It’s normal to feel sad, depressed, experience feelings of loneliness, or sometimes even lose hope, especially after a stressful life event or transition such as moving from a new city, falling out with a friend, working in a high-stress field, or getting a divorce.
However, if symptoms become ongoing, persistent, and impact daily functioning, this could be a sign of a depressive disorder. Two of the most common types of depressive disorders affecting nearly 20% of Americans are Major Depressive Disorder (MDD) and Persistent Depressive Disorder (PDD) [1].
The key difference between MDD and PDD lies in the severity and duration of symptoms: MDD involves intense depressive episodes lasting at least two weeks, while PDD is characterized by a milder but chronic low mood that persists for at least two years.
Understanding this difference between the two helps patients receive an accurate diagnosis and ensures treatment plans are personalized and effective.
What is Major Depressive Disorder (MDD)?
Major depressive disorder is when an individual struggles with a major depressive episode that lasts at least two weeks and causes significant changes to mood, activities, and a lack of pleasure in everyday activities. During a depressive episode, symptoms might include:
- Changes in appetite or weight
- Changes in sleep
- Fatigue, reduced motor activity
- Feelings of shame, guilt, hopelessness, or worthlessness
- Trouble focusing and making decisions
- Substance use
- Self-harm, suicidal thoughts, or suicidal attempts
People with MDD often describe feeling hopeless, they may also struggle with feelings of anxiety and restlessness, or be emotionally numb and not feel anything at all. Unresolved depression can manifest as physical health problems such as chronic digestive problems, aggression, or behavior difficulties (e.g., reduced work performance) [1].
What is Persistent Depressive Disorder (PDD)?
Formerly known as dysthymia, PDD is considered a chronic form of depression. It is characterized by a depressed mood most of the day, more days than not, lasting for at least two years in adults and one year in children or teens. Persistent depression is thought to affect around 2% to 5% of the US population [2].
Symptoms are similar to major depression, but generally less severe and last longer. It’s normal for individuals to experience low energy, poor appetite or overeating, sleep problems, and low self-esteem. Symptoms cause significant distress or impairment in social, occupational, or important areas of functioning [2].
MDD vs PDD: A Quick Glance
The main differences in Persistent Depressive Disorder (PDD) and Major Depressive Disorder (MDD), according to the DSM-5 criteria, are [1][2]:
| Disorder | MDD | PDD |
| Duration | Diagnosed when symptoms last for at least 2 weeks per episode. | Depressed mood most of the day, more days than not, for at least 2 years in adults, 1 year in teens/children. |
| Symptom Severity | Symptoms are often more intense, but don’t last as long. Self-harm, aggression, and suicidal ideation are typically more common in MDD episodes. | Symptoms are generally milder but chronic. They last all day, every day, and for the long term. |
| Symptom Amount | Requires at least five symptoms, including either depressed mood or loss of interest/pleasure. | Involves fewer symptoms (at least two from the criteria list) |
| Course | Episodes of major depression, with symptom-free intervals of at least 2 months. | Chronic low-level depression without symptom-free periods longer than 2 months, although major depressive episodes can occur during PDD (called double depression). |
| Treatment | Acute stabilization through medication or inpatient care may be necessary during episodes of MDD. | Treatment plans may be longer, and often focus on maintaining adherence to therapy over time, with regular follow-ups to monitor symptoms and adjust treatment as needed. |
What Causes Depressive Disorders?
Unlike seasonal depression, which is linked to changes in weather and daylight patterns, and premenstrual dysphoric disorder (PMDD), which is tied to cyclical hormonal fluctuations before menstruation, Major Depressive Disorder (MDD) and Persistent Depressive Disorder (PDD) do not have a single known cause.
Both are thought to share similar biological, environmental, and psychological influences, and their biggest differences are in symptom presentation, duration, and severity.
Several factors that play a role in the development of both MDD and PDD include [3][4]:
- Smaller Hippocampus: fMRI imaging studies show that those diagnosed with depression have a smaller hippocampus (a brain region that plays a role in mood and emotions) than those without.
- Changes in Grey Matter: Imaging shows reductions in grey matter in certain regions, which play a key role in helping distribute neurotransmitters and nutrients throughout brain regions.
- Trauma: Childhood trauma, work trauma, domestic abuse, and adverse life experiences significantly increase the risk of developing depression. Trauma can alter brain chemistry and stress response systems, leading to greater vulnerability to depression.
- Drugs and Alcohol: Substance use can contribute to and exacerbate symptoms of depression. These can disrupt neurotransmitter balance and brain function, worsening mood regulation and increasing depressive episodes.
Are MDD and PDD Treated Differently?
Treatment for MDD and PDD is similar, with both responding to medications such as selective serotonin reuptake inhibitors (SSRIs) or cognitive behavioral therapy (CBT).
SSRIs target chemical imbalances of neurotransmitters in the brain, while CBT offers evidence-based strategies for restructuring negative thoughts and developing positive coping skills.
Treatment for MDD may require more immediate or intense interventions, especially during depressive episodes where drug use, self-harm, or aggression are present. However, long-term treatment plans and hospitalization rates are more common in those with PDD due to chronic functional impairment [5].
Advanced Treatments for Complex Cases of Depression at Maple Mountain
For those who have tried multiple medications and therapy with little to no relief in symptoms, advanced treatments such as Transcranial Magnetic Stimulation (TMS) and ketamine therapy are designed for those facing treatment-resistant, chronic depression.
Ketamine is a dissociative anesthetic administered in controlled, supervised sessions. It targets brain pathways that conventional antidepressants often miss to improve mood and emotional regulation. It also sparks insights and neuroplasticity, and encourages increased motivation and self-change.
FDA-approved TMS therapy stimulates specific brain regions associated with mood regulation using magnetic pulses. TMS is designed to strengthen neural circuits and strengthen emotional resilience.
Healing Depression in Utah
At Maple Mountain, these advanced therapies are integrated into personalized, multidisciplinary care plans, ensuring each client receives compassionate support tailored for chronic depression.
Our compassionate team can help you verify insurance benefits and set up a personalized treatment plan that meets your unique mental, physical, financial, emotional, and spiritual needs. Contact our admissions team today.
Sources
[1] National Institute of Mental Health. Major Depression.
[2] National Institute of Mental Health. Persistent Depressive Disorder (Dysthymic Disorder).
[3] What causes depression? 2022. Harvard Health.
[4] Blakey, Shannon. 2019. Why do trauma survivors become depressed? Testing the behavioral model of depression in a nationally representative sample. Journal of Psychiatry Research.
[5] Kolter, M. Chronic vs non-chronic depression in psychiatric inpatient care – Data from a large naturalistic multicenter trial. Journal of Affective Disorders.
