1. Analytical (e.g. Macroprolactinemia)

2. Physiological

      a. Pregnancy

      b. Lactation

      c. Stress

3. Pharmacological

      a. Anti-psychotics (e.g. risperidone)

      b. Anti-hypertensives (e.g. verapamil)

      c. Anti-depressants (e.g. tricyclic antidepressants)

     d. Anti-epileptic drugs

     e. Metoclopramide

     f. Opiates

     g. Estrogens (e.g. oral contraceptives)

4. Pathological

      a. PRL secreting adenomas

      b. Hypothalamic/pituitary stalk disorders (e.g. granulomatous disease, irridation, trauma)

      c. Renal dysfunction

      d. Hepatic failure

      e. Hypothyroidism

      f. Hereditary disorders

5. Idiopathic