Taking sertraline for 20 days or emotional instability may be caused by the lack of symptomatic use of medication, small dosage of medication or continued external stimuli. 1. not the right medicine: sertraline can be used to treat depression and obsessive-compulsive disorder and other diseases, the patient did not take sertraline for 20 days to stabilize the condition, then the patient can appear mood is still unstable symptoms. 2. small dosage: patients taking sertraline under the guidance of a doctor to change the dosage of their own, will lead to the dosage is relatively small, is not conducive to the drug to play the proper therapeutic effect, which can also appear in the above symptoms. 3. Continuous external stimulation: When patients are continuously exposed to external stimulation during the period of taking the drug, it will lead to the aggravation of the condition, and even if they are taking the drug, they may still have the symptom of emotional instability. Adverse reactions include insomnia, headache, dizziness, diarrhea, nausea, vomiting and dry mouth. It is contraindicated for those who are allergic to the product and the ingredients contained in it. Combination with monoamine oxidase inhibitors, pimozide and other drugs is prohibited. It is not suitable for pregnant and lactating women. Taking sertraline for 20 days or emotional instability may also be caused by other reasons, patients are advised to go to the hospital as soon as possible to receive treatment.