I have major depression and i do high intensity intervals workout.if i take 5 grs of creatine each day, it helps to reduce my depression?weight gain?

Unknown: Creatine is a popular supplement & it will increase your muscle mass & body weight. There is a small published study claimed that 5 Gms of daily creatinine will help in depression. Data on this matter are insufficient and needs more study. At present no FDA recommendation. Check your kidney function and CPK regularly if you to take it. Above all talk to your PCP about it.

Not enough evidence: According to the National Institute of Health there is insufficient evidence to rate the effectiveness of creatine as it applies to the treatment of depressive symptoms. When used at recommended doses the substance is rated as POSSIBLY SAFE. When exceeding these doses it is rated as POSSIBLY UNSAFE. Here is a link you may find useful: http://www.nlm.nih.gov/medlineplus/druginfo/natural/873.html