Situation: A 40-year-old woman is admitted to the psychiatric ward with major depressive disorder. She has lost 3 kg in 4 weeks, eats about half of each meal, sleeps 3 to 4 hours a night, and says worrying thoughts keep her awake at bedtime. Her vital signs are within normal limits. The nurse writes nursing diagnoses using NANDA International (NANDA-I) 2024–2026 labels. A student looks up her psychiatric diagnosis in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). Under which chapter of this manual is major depressive disorder classified?

Since DSM-5, the former mood disorders chapter has been split into two chapters: bipolar and related disorders, and depressive disorders. Major depressive disorder is in the depressive disorders chapter; DSM-5-TR has no chapter called mood disorders.

DSM-5-TR classification of major depressive disorder

The correct chapter is Depressive disorders. In DSM-5, the previous single chapter called Mood disorders was formally divided into two separate chapters: Bipolar and related disorders and Depressive disorders. Major depressive disorder (MDD) belongs to the depressive disorders chapter, not to a chapter labeled mood disorders, because that chapter no longer exists in DSM-5 or DSM-5-TR ^[1].

This structural change matters clinically because it reflects a conceptual separation between unipolar depression and bipolar illness. In DSM-IV, depressive episodes and manic episodes were grouped together under the broad umbrella of mood disorders, which could blur the distinction between conditions that have different courses, risks, and treatments. By placing MDD in its own chapter, DSM-5 emphasizes that unipolar depression is diagnostically and therapeutically distinct from bipolar spectrum disorders ^[1]. For nursing practice, this means that when a patient presents with depressive symptoms, the clinician must actively assess for any history of mania or hypomania; if present, the diagnosis shifts to the bipolar chapter rather than remaining under depressive disorders.

A second important point from the DSM-5 revision is the expansion of the core mood criterion. The wording change added hopelessness as an explicit component of depressed mood, which can broaden the recognition of MDD in patients who describe their state primarily as a loss of hope rather than sadness ^[1]. In the scenario, the patient reports worrying thoughts that keep her awake at bedtime, along with reduced sleep, poor appetite, and weight loss. These features are consistent with the depressive disorders chapter, but the diagnosis of MDD also requires that the symptoms cause clinically significant distress or impairment and are not better explained by another condition.

Watch out! Do not choose Mood disorders. That chapter title was used in DSM-IV but was eliminated in DSM-5 and remains absent in DSM-5-TR ^[1]. A test item that lists mood disorders as an option is checking whether you know the current manual structure.

Key point! The DSM-5 reorganization into separate bipolar and depressive disorders chapters means that a patient with only depressive episodes is classified under depressive disorders, while any lifetime manic or hypomanic episode moves the diagnosis to bipolar and related disorders. This distinction guides medication selection, because antidepressants used for MDD can trigger mania in bipolar depression if mood stabilizers are not in place.

The patient’s presentation—3 kg weight loss over 4 weeks, eating about half of each meal, and sleeping only 3 to 4 hours per night—reflects the neurovegetative symptoms commonly seen in MDD. These are not diagnostic of the chapter itself, but they support the clinical picture of a depressive disorder. The nursing diagnoses written using NANDA-I labels would address problems such as imbalanced nutrition, insomnia, and anxiety, all of which flow from the underlying depressive disorder classified in DSM-5-TR under the depressive disorders chapter ^[1].