## **Core Concept**
The patient's presentation includes symptoms such as sadness, palpitations, loss of appetite, and insomnia, which are characteristic of depressive disorders. However, the absence of hopelessness, suicidal thoughts, and a past history of precipitating events suggests a milder or specific form of depression.

## **Why the Correct Answer is Right**
The symptoms described—sadness, palpitations, loss of appetite, and insomnia—without hopelessness or suicidal thoughts, and with no significant impairment in social and occupational functioning, point towards **Adjustment Disorder with Depressed Mood**. This condition is characterized by the development of emotional or behavioral symptoms in response to one or more identifiable stressors, but the symptoms do not meet the full criteria for a major depressive disorder. The fact that she is functioning normally in her office job and social life supports this diagnosis.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Without specific details on the options provided, we can infer based on common psychiatric diagnoses:
- **Major Depressive Disorder (MDD)** typically requires at least two weeks of depressed mood or loss of interest and at least five of the specified symptoms, including possible changes in appetite, sleep, energy level, concentration, or self-worth. The absence of hopelessness and suicidal thoughts and her normal functioning make this less likely.
- **Anxiety Disorder** might present with palpitations and insomnia but doesn't fully account for the depressed mood and loss of appetite.
- **Bipolar Disorder** would require episodes of mania or hypomania, which are not mentioned.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **Adjustment Disorders** are characterized by their direct relationship to a stressor and the symptoms typically resolve once the stressor is removed or managed. The presence of significant distress or impairment in social, occupational, or other areas of functioning is required for the diagnosis.

## **Correct Answer:** D. Adjustment Disorder.