Addison’s disease can present with symptoms similar to which of the following disorders?

Explanation

## Correct Answer: B. Depression Addison's disease (primary adrenal insufficiency) presents with profound fatigue, anhedonia, loss of interest, psychomotor retardation, and depressed mood—a clinical picture that mimics major depressive disorder. The mechanism is **cortisol deficiency**, which impairs monoamine neurotransmission (serotonin, norepinephrine, dopamine) and disrupts the hypothalamic-pituitary-adrenal (HPA) axis. Indian textbooks (Harrison, KD Tripathi) emphasize that endocrine causes of depression—particularly thyroid and adrenal disorders—must be screened before diagnosing primary psychiatric illness. The classic presentation includes depression with constitutional symptoms (weight loss, hypotension, hyperpigmentation from elevated ACTH). In Indian clinical practice, Addison's disease is rare but must be excluded in patients presenting with treatment-resistant depression or depression with unexplained systemic symptoms. The cortisol replacement therapy (hydrocortisone 15–20 mg/day in divided doses) often resolves the depressive symptoms, confirming the organic etiology. This is why secondary depression from Addison's disease is a key differential diagnosis in psychiatry. ## Why the other options are wrong **A. Bipolar disorder** — Bipolar disorder is characterized by episodic mood elevation (mania/hypomania) alternating with depression, with distinct periods of euthymia. Addison's disease presents with sustained depression without manic episodes or the cyclical pattern typical of bipolar illness. While Addison's may cause mood symptoms, the absence of manic features and the presence of constitutional adrenal insufficiency signs (hyperpigmentation, hypotension) distinguish it from bipolar disorder. This is an NBE trap pairing mood disorders without considering the organic context. **C. Panic disorder** — Panic disorder is defined by recurrent, unexpected panic attacks with autonomic hyperarousal (tachycardia, tremor, chest pain, fear of dying). Addison's disease causes hypotension and bradycardia, not the sympathetic hyperactivity seen in panic. Although fatigue and anxiety may coexist in Addison's, the cardinal feature is depression with hypoarousal, not the acute episodic panic attacks with hyperarousal that define panic disorder. The clinical presentation and pathophysiology are fundamentally different. **D. Generalised anxiety disorder** — Generalised anxiety disorder (GAD) is characterized by persistent, excessive worry across multiple life domains with hyperarousal symptoms (restlessness, irritability, muscle tension). Addison's disease presents with depression, fatigue, and hypoarousal—the opposite of the sustained anxiety and tension in GAD. While some anxiety may occur in Addison's, the predominant mood disturbance is depression, not anxiety. The cortisol deficiency causes CNS depression, not the anxious hyperarousal of GAD. ## High-Yield Facts - **Addison's disease** presents with depression, fatigue, anhedonia, and psychomotor retardation—mimicking major depressive disorder. - **Cortisol deficiency** impairs monoamine neurotransmission (serotonin, norepinephrine, dopamine), causing secondary depression. - **Screening for endocrine causes** (TSH, cortisol, ACTH) is mandatory in treatment-resistant depression or depression with constitutional symptoms. - **Hydrocortisone replacement** (15–20 mg/day) resolves depressive symptoms in Addison's, confirming organic etiology. - **Hyperpigmentation and hypotension** are clinical clues distinguishing Addison's-related depression from primary psychiatric depression. ## Mnemonics **ADDISON'S MOOD MIMIC** **A**nhedonia, **D**epression, **D**epressed affect, **I**nactivity, **S**ystemic signs (hypotension, hyperpigmentation), **O**rganic cause (cortisol ↓), **N**eed screening (cortisol, ACTH), **S**econdary mood disorder. **ENDOCRINE DEPRESSION SCREEN** **T**hyroid (TSH), **A**drenal (cortisol, ACTH), **P**ancreas (glucose) — TAP screening for secondary depression in Indian clinical practice. ## NBE Trap NBE pairs Addison's with bipolar disorder to lure students who conflate "mood disorder" with "any psychiatric presentation." The key discriminator is the absence of manic episodes and the presence of constitutional adrenal insufficiency signs (hyperpigmentation, hypotension, elevated ACTH) that point to secondary depression, not primary bipolar illness. ## Clinical Pearl In Indian tertiary care, a patient presenting with treatment-resistant depression and unexplained weight loss, hypotension, or hyperpigmentation should trigger immediate cortisol and ACTH testing. Addison's disease is rare but devastating if missed—cortisol replacement can reverse the entire psychiatric presentation within weeks, making it a critical differential diagnosis that psychiatrists must screen for before labeling depression as "primary." _Reference: Harrison Ch. 352 (Adrenal Insufficiency); KD Tripathi Ch. 56 (Adrenocorticosteroids); Robbins Ch. 24 (Endocrine Pathology)_