Mood lability is best described as:

• A. Rapid, unpredictable shifts in mood
• B. Persistent sadness
• C. Elevated mood
• D. Lack of interest in activities

Answer: (A)

Mood lability describes rapid, unpredictable shifts in mood, where emotions swing quickly from one state to another rather than staying on a single level. This means someone might move from happiness to sadness, or calm to irritability, in a short span, often with little warning. That quick, inconsistent fluctuation is what sets mood lability apart from a mood that’s consistently sad (persistent sadness) or consistently elevated (elevated mood). It’s also not about a loss of interest in activities (anhedonia), which is about motivation and pleasure rather than the speed and variability of mood shifts. Mood lability signals affective instability and implies difficulties with regulating emotional responses, which can appear in several psychiatric conditions.