Differential Diagnosis I: MAJOR DEPRESSIVE DISORDER (MDD)
Rationale: Ashley presents with several signs and symptoms of major depressive disorder (MDD), including depressed mood, loss of energy, difficulty concentrating, insomnia, weight loss and recurrent thoughts of death (Center for Substance Abuse Treatment, 2008). A diagnosis of major depressive disorder can be made if the symptoms are severe enough to interfere with a person’s ability to sleep, study, eat and enjoy life (NIMH, 2015). Ashley’s testimony that she has had difficulty with school, sleep and volleyball practice therefore supports this diagnosis.
Differential Diagnosis II: GRIEF
Rationale: Ashley presents with symptoms of grief, including sadness and withdrawal from usual activities. Despite some overlap between grief and MDD, a couple key aspects can differentiate these two diagnoses: 1) In grief, feelings of sadness usually come in waves; in depression, negative mood is almost always sustained, 2) In grief, the patient maintains self-esteem; in depression, patient often has feelings of worthlessness or self-loathing (APA, 2013). Ashley’s history of prolonged feelings of worthlessness combined with her history of self-harm support a diagnosis of MDD rather than grief. Additionally, Ashley did not identify any specific trigger for her feelings of sadness (e.g. loss of a loved one), thus making a diagnosis of grief unlikely.
Differential Diagnosis III: BIPOLAR DISORDER
Rationale: Ashley presents with symptoms commonly associated with the depressed phase of bipolar disorder, such as a depressed mood and suicidal ideation. Patients experiencing a depressive episode of bipolar disorder have a very similar clinical presentation to a patient with MDD (also called unipolar depression) (Hirschfield, 2014). A key aspect of bipolar disorder that differentiates it from MDD is that patients with bipolar disorder also experience manic episodes. The fact that patients rarely present to the health care provider during a manic episode of BPD can complicate the differential diagnosis (Tesar, 2010). In order to diagnose a patient like Ashley with bipolar disorder, she would have to describe a past history of manic episodes. Since Ashley did not describe a history of manic episodes, the clinician would likely not make a diagnosis of bipolar disorder at this encounter.
Of note, antidepressants show little to no efficacy for depressive episodes associated with bipolar disorder (Hirschfield, 2014). Consequently, correct identification of bipolar disorder among patients exhibiting signs of depression is critical for effective treatment and improved outcomes (Hirschfield, 2014).
