A couple of things: I don’t think it is possible to say absolutely what the side effects of any drug will be in any individual. Sexual side effects are very common with antidepressants but you can’t know for certain how they will effect you. And the side effects can be dose dependent, I think. You have no way of knowing what a therapeutic dose could be for you; you could respond to relatively lower dose that would have relatively fewer or less severe side effects. You won’t know until you try it. And though I respect the advice that @Joybird has offered, regarding alternate treatment options I would urge you to work very closely with your doctor on this. A traumatic brain injury is nothing to fool around with. I’m certainly not a doctor and I don’t know what kind of brain injury you’ve had but, if for example, it has possibly put you at increased risk for seizures you need to be careful both about the medication you take and about any alternative treatments like biofeedback. And if you any reason at all to suspect or believe that your doctor or doctors are talking “in absolutes” and making medical decision based on “what’s easiest for them and most cost effective” as @Joybird puts it, rather than on what’s best and most appropriate in your_ case, for your health, then I very strongly urge you to find another doctor. It just seems that there may be some important medical issues involved in healing from a traumatic brain injury, and while you should certainly be an informed and intelligent “consumer” of “medical services,” who should work with your doctors; they’re not gods who should simply be obeyed without question or thought, but I’m not sure if you telling them what your treatment plan should be is the way to go. If it is, why consult a doctor at all, if not for their medical knowledge and expertise?
And just in case you’re interested, here’s a link to some standard AMA information on sexual side effects of antidepressants and possible ways to deal with them. And here’s a link to a forum discussion about the different reactions some people have had to Celexa.
Good luck.