A man maintains a sociable, cheerful manner throughout a consultation, explaining he does not want to burden his family, yet on careful, direct questioning discloses profound hopelessness, loss of interest in everything, and significant suicidal thinking that his outward presentation gave no hint of. What is this?

This is smiling depression: significant depressive illness presented outwardly with a maintained smile or cheerful manner, here explicitly to avoid burdening others, masking severe underlying symptoms including suicidal thinking, exactly as described. It is not la belle indifférence, since smiling depression differs from la belle indifférence, which concerns unconcern about a specific physical symptom rather than a maintained cheerful front over an underlying depressive illness; here there is no physical symptom involved at all. It is not affect blunting, which is a reduced range and intensity of emotional expression across the board, not a maintained, effortful cheerful display over a genuinely severe underlying mood disturbance. And it is not demoralization, in which low mood stays closely tied to a specific struggle without the pervasive loss of interest and energy seen here, and without the deliberately maintained cheerful front.