Premenstrual syndrome (PMS)

Premenstrual syndrome is a recurring pattern of physical and emotional symptoms that appears in the days before a menstrual period and eases once bleeding begins.

Typical physical symptoms include bloating, breast tenderness, headache, fatigue and food cravings, while emotional symptoms include irritability, low mood, anxiety and difficulty concentrating. The pattern is tied to hormonal changes in the second half of the cycle, though why some women are more sensitive to those changes is not fully understood. A more severe form with disabling mood symptoms is classified separately as premenstrual dysphoric disorder.

Diagnosis rests on prospective symptom tracking across at least two cycles, confirming that symptoms cluster in the premenstrual phase and lift afterward, with other conditions such as thyroid disease or depression excluded. Cannabinoids have been examined mostly through surveys of women's self-reported use, and controlled research on premenstrual symptoms is lacking.