Here is some info that you may find helpful. As far as my research goes, Lamotragine is being used as a third line of treatment for refractory trigeminal neuralgia and peripheral neuropathy. These are specific terms referring to specific types of pain caused by specific maladies. I have found no other condition involving pain that this med treats. This does include back pain. A couple different studies support this. BTW neuropathy involves the symptoms from damaged nerves. The article Lamotrigine | InHealth Pain Management Solutions provides a more complete listing of conditions related to the type of pain that this med treats. The jury appears to be out on fibromyalgia.

FYI Flat affect is not listed as a side effect for Lamotragine. There are APs with this listed side effect. According to my research, Lamotragine acts differently from APs and other mood stabilizers in mood regulation. Instead of being used to prevent ones mood to swing up into mania, it decreases the number of occurrences of mood swings. This is the key difference between this med and others used to stabilize mood. This is probably why many docs do not find this med sufficient and prescribe other meds in conjunction with lamotragine to regulate mood. So IMO based on this research I doubt it is this med that has caused you your flat affect. But we shall see. Good luck.

As you can see, I have done my research on psychotropic meds, more specifically the meds that I am prescribed. You likely have done the same. For that matter, your decades experience with lamotragine and other meds must of made you aware of all this. So this is probably no news to you.

PS By this post, I am trying to help you make intelligent decisions regarding your use of meds. I do not think I am judging you with this post. As you know, at the very least, you need to do your due diligence before changing your meds by yourself. At least I hope this is the case for you.