Sorry I'm a little late on this, but I have not seen Lamictal cause any weight gain, or fatigue, I think it's a great med, it is not only used for Bipolar, it is an anti-seizure med. used for epilepsy and migraines. It may even be used for other stuff. It's like a multi-purpose kind of med. of what I've heard/read. My regular dose was 200mgs daily, and now I'm down to 150mgs, which my pdoc told me anything lower would no longer be therapeutic, so my lowest therapeutic dose is now the 150mg.
As long as your pdoc titrates you up in the proper increments (mgs) I do not think you will notice any negative effects, but meds can effect people differently so I'm only sharing my own experience with this med.
Once I had started with Lamictal I no longer needed any anti-depressants, besides the SSRI's no longer worked for me, I experienced SSRI "poop out" which is not an unusal occurance when those kind of AD's are used over a length of time and/or that is really not the type of med. the person needed or needs.
It is always in the person's best interest to be evaluated by a pdoc if any psychiatric type med is needed, many GP's are getting overly involved with writing prescriptions for AD's and other type meds used for many different kinds of mental disorders and are really not as qualified as a pdoc, who's expertise is treating mental disorders/traumas,etc.
Like one wouldn't go to a dentist for their heart condition,a diabetic wouldn't go to an orthepedic doc to treat and follow the diabetic's condition and insulin meds.
So it is important to go to the right kind of doctor for the
particular disorder and/or illness.
Lots of luck with this.