A person who exhibits significant changes in behavior, such as lack of interest in previously enjoyed activities after a traumatic loss, is likely dealing with what?

The scenario described illustrates a significant change in behavior following a traumatic loss, particularly characterized by a loss of interest in activities that were previously enjoyable. This symptom of anhedonia, along with the context of having experienced a traumatic event, aligns closely with Major Depressive Disorder.

Major Depressive Disorder is marked by a persistent feeling of sadness or a lack of interest in previously pleasurable activities. Changes in appetite, sleep disturbances, feelings of worthlessness, and difficulty concentrating may also be present. The timing of these symptoms, specifically following a traumatic experience, further supports the diagnosis, as grief and depression can frequently overlap.

While other disorders mentioned, such as Panic Disorder with Agoraphobia and Post-Traumatic Stress Disorder, can also involve significant changes in behavior, they typically present with a different symptom profile. Panic Disorder primarily involves episodes of intense fear, while Post-Traumatic Stress Disorder often includes flashbacks, hyperarousal, or avoidance of reminders related to the trauma. Dissociative Amnesia tends to center around memory loss directly related to trauma rather than changes in interest or engagement in activities.

Therefore, the individual's behavior, notably the loss of interest following a traumatic event, strongly indicates Major Depressive Disorder as the most fitting diagnosis.