Patient description: The patient is a 47-year-old Asian woman complaining of persistent feelings of sadness. She lost interest in activities she used to enjoy. She states that her mood is mostly depressed for the past 3 weeks. She also lost her appetite , which led to about 5kg weight loss. She complains of loss of energy and feelings of worthlessness nearly every day. She is not using any drugs and she does not smoke. She doesn't drink alcohol. She used to exercise every day for at least 30 min. But she doesn't have enough energy to do so for the past 3 weeks. She also has some digestive issues recently. She is married and has 4 children. She is menopausal. Her husband was recently diagnosed with colon cancer and he is starting his chemotherapy. There is nothing remarkable in her past medical history and her drug history is only positive for Vit D3 1000 units daily. Her family history is negative for any psychologic problems. Her HAM-D score is 20.

Clinical trial eligibility criteria: eligible ages (years): 18.0-50.0,  Depression Participants will be required to be in good general health (as evaluated during the phone and in-person screening sessions described below), and to be between 18-50 years of age. All participants will be required to be fluent in English and to be right-handed  Following a structured telephone interview, prospective participants with the following conditions will not advance to the in-person screening session: claustrophobia or presence of metal in their body (relevant for the neuroimaging component of the study), pregnant or planning to become pregnant in the next 6 months, presence of chronic mental or physical illness, history of allergies, autoimmune, liver, or other severe chronic diseases, current and regular use of prescription medications, nightshift work or time zone shifts (> 3hrs) within the previous 6 weeks, or previous history of fainting during blood draws. Furthermore, the absence of significant health problems or medication use history will be confirmed by an in-person screening session. Any participant who has any of the following conditions will be ineligible for the study: Medical conditions. (1) presence of co-morbid medical conditions not limited to but including cardiovascular (e.g., history of acute coronary event, stroke) and neurological diseases (e.g., Parkinson's disease), as well as pain disorders; (2) presence of co-morbid inflammatory disorders such as rheumatoid arthritis or other autoimmune disorders; (3) presence of an uncontrolled medical condition that is deemed by the investigators to interfere with the proposed study procedures, or to put the study participant at undue risk; (4) presence of chronic infection, which may elevate proinflammatory cytokines; (5) presence of an acute infectious illness in the two weeks prior to an experimental session. Psychiatric Disorders. (6) current and/or lifetime history of a major Depressive Disorder or other DSM-IV psychiatric disorder (e.g. substance dependence) due to the known effects of major depression and/or substance dependence on inflammation. (Absence of a psychiatric diagnosis will be based on a structured psychiatric interview (Structured Clinical Interview for DSM-IV Diagnosis: SCID; First et al., 1996).) Medication and substance use. (7) current and/or past regular use of hormone-containing medications including steroids; (8) current and/or past regular use of non-steroid anti-inflammatory drugs; (9) current and/or past regular use of immune modifying drugs that target specific immune responses such as TNF antagonists; (10) current and/or past regular use of analgesics such as opioids; (11) current and/or past regular use of psychotropic medications, including selective serotinergic reuptake inhibitors, antidepressants, anxiolytics, hypnotics, sedatives and barbiturates. Health factors. (12) current smokers or excessive caffeine users (>600 mg/day) because of known effects on proinflammatory cytokine levels; (13) body mass index (BMI) greater than 35, (14) shows evidence of drug use from a positive urine test, (15) has a positive pregnancy test, if female, or (16) shows any abnormalities on screening laboratory tests