Major Depressive Disorder (MDD), often referred to as clinical depression, is a severe and common mood disorder. It goes beyond temporary feelings of sadness or everyday stress. MDD is a clinical condition that deeply affects how a person feels, thinks, and handles daily activities such as sleeping, eating, and working.
For students preparing for health science and psychology entrance exams, understanding the exact clinical criteria for MDD is essential. You must be able to distinguish a clinical diagnosis from normal emotional fluctuations.
The Diagnostic Criteria
To be diagnosed with Major Depressive Disorder, a person must experience a specific set of symptoms for at least two weeks. These symptoms must represent a change from the person’s previous level of functioning and cause significant distress or impairment in social, occupational, or other important areas of life.
Core Symptoms
A diagnosis requires the presence of at least one of the following two core symptoms nearly every day:
- Depressed mood: Feeling sad, empty, or hopeless most of the day.
- Anhedonia: A significant loss of interest or pleasure in all, or almost all, activities that were once enjoyed.
Additional Symptoms
In addition to a core symptom, the individual must experience enough of the following symptoms to reach a total of at least five symptoms overall:
- Appetite or weight changes: Significant, unintentional weight loss or gain, or a noticeable decrease or increase in appetite.
- Sleep disturbances: Insomnia (difficulty falling or staying asleep) or hypersomnia (sleeping excessively).
- Psychomotor changes: Observable physical restlessness (agitation) or a noticeable slowing down of physical movements and speech (retardation).
- Fatigue: A severe loss of energy or feeling tired nearly every day.
- Feelings of worthlessness or guilt: Excessive, inappropriate guilt or feeling completely worthless.
- Cognitive difficulties: A reduced ability to think clearly, concentrate, or make decisions.
- Suicidal ideation: Recurrent thoughts of death, suicidal thoughts without a specific plan, or a specific plan or attempt to commit suicide.
Why This Matters for Treatment
Understanding these specific symptoms is the foundation for studying depression treatments. When we look at how physical activity and exercise impact MDD later in this course, we will measure success by how well exercise reduces these specific clinical symptoms—such as improving sleep, restoring energy levels, and enhancing cognitive function.