A client with major depressive disorder reports: 'I've been feeling much better lately. I've given away my jewelry and written a goodbye letter to my children.' What is the nurse's priority concern?

PARADOXICAL IMPROVEMENT IN DEPRESSION is a well-documented and dangerous phenomenon: EXPLANATION: Severely depressed clients often lack the energy to act on suicidal thoughts; when they 'improve' slightly, they have enough energy to act but their hopelessness has not resolved; their apparent improvement may actually reflect a decision to act — the 'calm before the storm'; BEHAVIORAL WARNING SIGNS OF IMMINENT SUICIDAL INTENT: Giving away valued possessions (rings, jewelry, meaningful items); saying goodbye in unusual ways; writing final notes/letters; sudden calm after prolonged distress; putting affairs in order; IMMEDIATE NURSING ACTIONS: DO NOT leave the client alone; NOTIFY physician/psychiatrist immediately; implement safety precautions (1:1 observation, remove ligatures and sharps, check belongings); REASSESS suicide risk using validated tool; HOSPITALIZATION is likely indicated. NEVER interpret these signs as reassuring improvement without thorough investigation.