call me crazy-
18mg would just be a very low starting dose for Strattera. It is very possible you would see no effect at all on that dose. Adolescent and adult starting dose reccomended by the manufacturer is 40mg/day. In Dr Jain’s lecture series he explained the optimal effect with Strattera is seen at 1.1mg/kg which would mean about 80mg/day for you, I believe. It could be your doc started you on a low dose to try and ease it’s side effects. Has he talked about bumping your doseage?
I was started at 25mg (second time around on the med after evaluating a half dozen or so different ADD meds) as I was pretty sensitive to side effects when I was on it before. My schedule was to be 25 mg 2-3 weeks, 40 mg for 2-3 weeks, 65 mg for 2-3 weeks and then -depending on side effects and results- looking at 80mg and higher dosages. At my weight ,110mg/day calculates out as “optimal”.
Also, Jeneticallymodified makes an EXCELLENT point. Sometimes we are not the best people to judge a medication’s effectiveness. Talk to those closest to you (parents, significant other, best friend, co-workers) and see what their thoughts are. There may have been some very subtle changes you were not aware of. Even though the manufacturer states it typically takes 1-4 weeks to see results from Strattera, the first time I was on it I myself noticed significant improvement after only 2 or 3 days. Of course meds work differently on everyone so your mileage may vary 