Pot can have a positive effect, but you can get a step or three closer to the root of the problem by supplementing amino acids.
A relative who's an engineer has had a great experience with it via the book The Mood Cure, which is a self-help approach that helps you figure out which of four types of amino acids you're short of. He gave us a copy and I needed all four (other members of my family needed between one and four). This is my first workday on amino acid supplements and it's going way, way better than has been the case recently (I'm on HN voluntarily instead of automatically).
The book details ways that marijuana and other drugs (both uppers and downers) work on the mental balance, and explains why and how amino acids are an improvement. Lots of specifics on that topic -- the author certainly agrees that drugs are helping people.
Diet and liver health are another level down and VERY important to get in line, but amino supplements can get you where you want to be in minutes while you work on fixing the root cause gradually.
On another front, RescueTime has a "Get Focused" mode that works great.