How can I differentiate between premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD) in my patients?

To differentiate between premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD) in your patients, focus on the severity, type, and impact of symptoms occurring in the luteal phase of the menstrual cycle.

PMS is characterised by a range of physical and emotional symptoms such as bloating, breast tenderness, mood swings, and irritability that are mild to moderate in severity and do not significantly impair daily functioning ¹. In contrast, PMDD is a severe form of premenstrual disorder marked predominantly by affective symptoms including marked mood lability, irritability, severe depression, anxiety, and tension, which cause substantial distress and interfere markedly with work, social activities, and relationships ¹ (Johnson, 2004).

Key differentiators include:

• Symptom severity and functional impairment: PMS symptoms are generally less severe and do not disrupt daily life, whereas PMDD symptoms are severe enough to cause significant impairment ¹ (Johnson, 2004).
• Symptom type: While PMS includes both physical and emotional symptoms, PMDD is characterised mainly by prominent mood symptoms such as marked irritability, anger, depressed mood, and anxiety (Johnson, 2004) ¹.
• Timing and cyclical pattern: Both conditions occur in the luteal phase and resolve shortly after menstruation begins, but PMDD symptoms are more consistent and predictable in their timing and severity ¹ (Johnson, 2004).
• Diagnostic criteria: PMDD diagnosis requires prospective daily symptom charting over at least two menstrual cycles to confirm symptom pattern and severity, as per NICE and clinical guidance ¹.

In summary, the differentiation hinges on the intensity and impact of symptoms, with PMDD representing a more severe, mood-dominant, and functionally impairing condition compared to PMS ¹ (Johnson, 2004).