 Objectives: The effect of acupuncture as treatment for chronic pain and depression comorbidity is questionable because only a limited number of controlled clinical trials with sound methodologies have been conducted. The investigators will perform a well-designed crossover study including assessments of scales and blood sample analysis to investigate the efficacy of acupuncture as treatment for comorbidity of chronic pain and major depression disorder MDD and figure out the indicative biomarkers to predict or assess the comorbidity. 