Which mental health disorder is characterized by extreme variability in mood?

The disorder characterized by extreme variability in mood is indeed Borderline Personality Disorder. Individuals with this condition often experience intense emotional responses that can change rapidly. These mood swings can be triggered by interpersonal issues, perceived rejections, or stressors, leading to significant fluctuations between feelings of euphoria and deep sadness or anger.

People with Borderline Personality Disorder may also struggle with identifying and maintaining a stable sense of self, which contributes to the extreme emotional changes they experience. This condition can affect relationships, self-image, and overall functioning, as the individual's emotional state can often seem unpredictable to themselves and others.

In contrast, while Bipolar Disorder also involves mood changes, these shifts typically occur over a longer timeframe and are categorized into distinct episodes (e.g., manic, depressive), making them less episodic in everyday interactions. Depression and Anxiety Disorders do involve mood and emotional regulation challenges but do not present the same level of extreme variability found in Borderline Personality Disorder.