The terms "clinical depression" and "reactive depression" both refer to different types of depressive experiences, though they can overlap in some cases. Here’s a breakdown of the differences:
1. Clinical Depression (Major Depressive Disorder)

Definition: Clinical depression, also known as Major Depressive Disorder (MDD), is a mental health condition that involves a persistent feeling of sadness or loss of interest in activities, along with other symptoms that interfere with daily life. These symptoms can last for at least two weeks and may include changes in appetite, sleep disturbances, fatigue, feelings of worthlessness or guilt, trouble concentrating, and thoughts of death or suicide.
Cause: It is often thought to result from a combination of biological, genetic, environmental, and psychological factors. While stressful events can trigger or worsen it, it can also occur without any clear external trigger.
Duration: It can last for weeks, months, or even years if untreated. Episodes may recur.

2. Reactive Depression

Definition: Reactive depression, sometimes referred to as situational depression, is a type of depression triggered by a specific external event or stressful life situation, such as the death of a loved one, a job loss, or a divorce. This form of depression is usually temporary and fades as the person adjusts to or processes the event.
Cause: It is directly linked to an identifiable life stressor or trauma. While the depression might mimic clinical depression in terms of symptoms, the cause is clearly related to a specific event.
Duration: Reactive depression is typically shorter in duration compared to clinical depression, often improving once the individual comes to terms with or adjusts to the life event. However, in some cases, it may evolve into clinical depression if the symptoms do not improve.

Key Differences:

Cause: Clinical depression may not have a clear trigger and can be due to biological or chemical imbalances. Reactive depression is specifically triggered by an identifiable life event.
Duration: Clinical depression is more persistent and can last longer, whereas reactive depression tends to resolve as the person adapts to the life change or stressful event.
Treatment: Both can benefit from therapy and possibly medication, but treatment approaches may differ slightly depending on the cause and severity.

In practice, it can sometimes be hard to distinguish between the two, especially when a person with reactive depression experiences prolonged symptoms that evolve into more chronic or severe depression. In such cases, the person may be diagnosed with clinical depression.