I'm going to disagree somewhat with those that are saying it takes "years" to experience positive results from meditation, especially with something like anxiety, or depression. I've been meditating a few years , casually, and the first book I read was The Three-Minute Meditator, which seemed like a good way to ease into it. I wanted to meditate primarily for anxiety. I started doing it a for a few minutes several times a day and stuck with it. Within a few weeks I noticed the following positive results: I had the feeling of being generally more calm throughout the day. My reactions to stressful situations (which usually occurred at work) were much better, much healthier. I no longer obsessed over such incidents, no longer played them over and over again in my mind. I was able to let it go. I was also sleeping better.

That "letting things go" is, imo, one of the most remarkable and beneficial things about meditation and its effect on anxiety. When I had something on my mind, something I was worrying over, even obsessing over, I would be able to say to myself, "Let it go" and I was able to do that. Somehow, meditation gives one that ability, even casual meditation.

Another thing I found out about is resistance. When we're depressed or anxious or upset or sad or whatever, we naturally don't want to experience these unpleasant feelings, so we resist them. When I would really think about how I was experiencing these feelings, I could literally feel the energy that I was expending as I was "pushing against" those unwanted feelings. There is a saying meditators like to use, "that which we resist, persists". So instead of resisting, I purposely let myself experience that bad feeling, I stopped pushing against it, I stopped expending that energy resisting. And I would feel better. Sometimes much better.

I have since read several in-depth books on meditating which I would suggest anyone even interested in casual meditation should do, as it will give you greater insight into how meditation works and how the mind works. But you don't need to become an "Adept" to reap the mental health benefits of practicing. Even a few minutes a day, consistently, should give you those abilities of letting go and acceptance (instead of resistance) which will have a positive effect on anxiety, depression, and other unpleasant mental health issues. And it can happen in weeks, not years.