Yes taking Gabapentin can cause depression in people who otherwise don't experience much depression.
Some other side effects of Gabapentin are clumsiness or unsteadiness, constipation, diarrhea, difficulty speaking,
drowsiness or tiredness, dry mouth and nausea.
If you start experiencing some bad side effects of taking Gabapentin speak with your doctor to try and slowly get away from the medicine since Gabapentin can cause a persons health to start failing.