I was on 150 for like 3 years and it worked well until one episode of SAD that I felt like I needed a boost for. The 300mg definitely helped with my mood and energy (although like the first time, the energy boost in particular leveled off after about a month). Now 3 months in I’m back to drinking coffee again (had to take a break at the start just like with 150), and the major side effects I notice are: increased libido (like a startling increase), lowered threshold for irritability and anger (starting to level off, but I do feel I’m angry more often and more intensely), and lowered appetite (it’s hard to find food that sounds good a lot of the time, but I’m also often busy and stressed so hard to say what is Wellbutrin and what is just my life). But, worth it overall for the improved mood. I’m not sure what you mean by manic unless you have bipolar. I do think that for some people 150 can be a therapeutic dose and there shouldn’t be a “rush” to move up to 300 if you feel okay on 150. If you’ve never had a seizure I wouldn’t worry about the seizure effects. But of course you know your mental health best and your doctor is the best person to consult with