An argument for the moral permissibility of psychoactive drugs (The medical type)

There seems to be a weird stigma about using prescribed psychoactive drugs.  These sorts of drugs include antidepressants, like Prozac, stimulants, like Ephedrine, mood stabilizers, such as Lithium, or sedatives, like Klonopin.  Some people hold the belief that it is somehow immoral or unnatural to take these kinds of drugs.  Here's an argument that shows that if you're okay with other sorts of pain-relieving medicine, you should be okay with psychoactive drugs as medicine.

1.  Prescribed psychoactive drugs are relevantly similar to (physical) pain-relieving drugs.
2. It is not a big deal (i.e. morally permissible) to use (physical) pain-relieving drugs in a responsible manner.
3. Therefore, it is not a big deal to use prescribed psychoactive drugs in a responsible manner.

I'm going to expand on the first premise, but let me say something quick about the second premise.  Obviously psychoactive drugs can be abused.  But this is true for any drug out there.  The potential for abuse is not something unique to psychoactive drugs, and is therefore not a good reason to think that it is morally questionable to use them.  The same can be said of potential side effects and possible addiction.

Okay, now on to the first premise.  We're all okay with using pain relievers like Ibuprofen, Tylenol, and Aspirin.  We're also okay with lots of other symptom repressing drugs like antihistamines, antacids, or various cold/flu medicines.  We are we okay with using these kinds of drugs?  Here's my guess.  Pain is a mental state.  It exists to alert the body that it is somehow in harm's way.  Once an individual has placed her body out of the potential source of danger, then the pain has served its purpose.  It is no longer useful at that point.  Many times, however, the pain still lingers even though we've taken the corrective measures.  This pain is not only superfluous, but can act as a detriment to our living our lives.  As a result, we take the sorts of pain relieving drugs mentioned above.

Emotions are also mental states.  They also serve as alerts to the individual.  They respond to stimuli in a similar way as pain does.  Negative emotions indicate external stimuli that may be psychologically harmful to the individual.  Once an individual has acknowledged such emotions and has taken the necessary steps to address the stimuli and has taken corrective measures, the emotion has served its purpose.  Like pain, however, negative emotions can also linger.  And, like pain, such emotions can be not only superfluous, but also harmful.  Psychoactive drugs repress negative emotions, like pain-relieving drugs repress the sensation of pain.

If you agree that this is a reasonable assessment of emotions, and if you are okay with taking pain-relieving drugs, then you should be okay with taking psychoactive drugs if you need them.  Now, it is important to note that it is only permissible to take such drugs to deal with superfluous negative emotions.  It is not okay to take such drugs in lieu of addressing the stimuli that is causally connected to the pain.  But this is also true of pain-relieving drugs.  It is obviously not okay to take pain-relieving drugs in lieu of actually dealing with the source of the pain.

Perhaps this is why the stigma exists.  It may not be clear if an individual has really dealt with the source of negative emotions, whereas it's usually pretty clear when an individual has dealt with the source of physical pain.