Yes, it can, although meditation alone has not been shown to be enough to deal with all mental health issues. Think of meditation as organized or regular relaxation exercises. It can take many forms, and can be as simple as finding one space during the day for as little as 15 minutes where there is no noise and no distractions and you can close your eyes.
The simple of act of concentrated breathing, a break for your mind from outside stimuli and a moment or two to clear your thoughts reduces stress, can lower your blood pressure, heart rate and anxiety, and leave you with a sense of peace and calmness. Like I said, that's never been shown to cure, say, schizophrenia or other clinical conditions, but there is certainly a positive effect on one's mental well being if it is done regularly enough.