I am certain there is some effect and will vary from person to person. Some cause drowsiness, blurred vision, and others may enhance reading as it will help focus. The two you mentioned are used in Bipolar, etc, treatment as well as an anti-seizure med. Again, it will vary based on what you are treating, dosage, etc. There are so many side effects and ADR’s that it is hard to say in sweeping general terms. The CNS is an amazing thing and it is common for changesusually (about 3–4) in meds for the same person to get to one that works right.