Patients who show a bronchospasmolytic effect in their functional pulmonary test (FEV1 increased by at least 5%) within four hours of taking montelukast also show a positive response (defined as a combination of at least two variables (see section on the definition of responders/non-responders during treatment)) after 12 weeks of treatment. Conversely, patients who show no acute effect do not have a positive response during long-term therapy.