Following a frontal lobe injury, a man persistently makes jokes and puns regardless of the seriousness of the conversation, seemingly unable to engage with a topic for long without lapsing into facetious remarks that feel shallow and hollow rather than genuinely witty or warm. What is this?

This is moria: a persistent tendency to make jokes, puns, or facetious remarks regardless of whether the situation is appropriate, with a shallow, hollow, or childish quality, often accompanied by other signs of frontal lobe involvement. It is not morbid euphoria, since the elevated mood here is specifically characterised by shallow, compulsive facetiousness rather than a broader expansive good mood or optimism. It is not ecstasy, which has a characteristic mystical, transcendent quality rather than persistent joking. And it is not lability of affect, which involves rapid shifts between markedly different emotional states, not a sustained, single facetious quality of mood.