<qa>  What is the name of the questionnaires that will be collected at 3 weeks?Eligible advanced NSCLC Patients with PHQ-9 score 8, and undertaking palliative chemotherapy will be enrolled into this study. After baseline assessment PHQ-9, HAMD-17 and EORTC QLQ-C30 questionnaires, 236 patients will be stratified gender, age, NRS score for cancer pain 0-34-67-10 randomized 1:1 into mirtazapine or placebo treatment. Patients in mirtazapine arm will be orally administered with mirtazapine 15mg, QD, consecutive medication for 8 weeks; along with palliative chemotherapy regimen decided by investigators. Patients in placebo arm will be orally administered with placebo 15mg, QD, consecutive medication for 8 weeks; along with palliative chemotherapy regimen decided by investigators. During the treatment, PHQ-9, HAMD-17 and EORTC QLQ-C30 questionnaires will be collected at 3 weeks d22 and 8 weeks d57, or treatment discontinuation date due to depression deteriorated or suicidal tendency and behavior. Follow-up will last up to 4 weeks after treatment end with depression assessment questionnaires every 2 weeks. If anti-depression therapy is not effective after 8 weeks treatment or treatment discontinuation, patients will be unblinded and receive other treatment according to investigators. Treatment end at 8 weeks. 