Here is some insight on moods vs emotions from When Hope is Not Enough:
Since I believe that the foundation for BPD is emotional dysregulation, most of the day-to-day conflicts, issues, rages and manipulative behavior spring from this feature of BPD. Emotional dysregulation is the engine that drives the train of BPD. Shame and impulsiveness also contribute no doubt (maybe as fuel and throttle respectively), but the engine itself is emotional dysregulation. In that way, BPD is much like a traditional mood disorder, such as bipolar disorder. The main feature that separates BPD from bipolar disorder is the length and frequency of the “mood” swings. Emotions are more fast-acting than moods and they can come and go quickly. In the DSM-IV, which is the mental health diagnostic manual used in the United States, the diagnostic guidelines refer to this quality within the BPD diagnosis guidelines this way:
- Affective instability due to a marked reactivity of mood (e.g., intense episodic dysphoria, irritability, or anxiety usually lasting a few hours and only rarely more than a few days).
The key to that and what distinguishes BPD from other mood disorders is the “usually lasting a few hours and only rarely more than a few days” part. Since emotions are short-lived, they will pass quickly through the mind of a BP. They will be intense (all emotions are) and may last longer than yours do, but emotions are immediate and normally will not last more than “a few hours” and more likely last only a few minutes. The intensity will typically be stronger than a “normal” person.