It depends upon what drug we are talking about. Some can enable speed (they are illegal), most do not.

Yes, I am very "anti-drug", and yes, I think there is drug abuse in horse racing, including steroids.

Some drugs enable the ability to perform, when a horse should be rested. Some of those drugs are good and necessary to racehorse health, some are abused or abusive by use.

Say your filly comes out of a hard race, and spends the next two days moping about her stall, not eating, significant weight loss, just wrung out by her effort, athough overall physically she's okay (not injured, etc).

Her vet giving her a certain legal steroid injection at the FDA-approved dose is good for her - it will get her eating and drinking well again, get her perky and happy, get her back to the track for light training - combined with good horsemanship regarding her training schedule, her next race scheduling, etc.

That steroid use may get her back to a next race in 5-6 weeks, rather than in 8-10 weeks.

That is NOT the same thing as "steroid abuse". Although, in Indiana, this type of good use - using the drugs for what they are intended, under veterinary supervision - may become problematic (that's another discussion).

A trainer or vet who is giving that same injection, in higher doses with more frequency, simply to get that filly to race back in two or three weeks, or keep her racing over months when she should be rested - that's abuse.

A trainer or vet who obtains non-FDA approved "designer" steroids, in an attempt to use a steroid-class drug without detection - that's abuse.

The public tends to lump all "drugs" together, unfortunately. They assume that reports of steroid abuse in humans are directly transferable to horses, and that all "steroid use" is the same. No, it isn't.

We've gone beyond that gross generality on this forum - talking about different classes of steroids, effects and side effects, etc. (but a smarter bunch here than "the general public", I think)

The majority of "steroid use" in horses are not the same "steroids" as Barry Bonds or Marion Jones used, nor does it necessarily get the same result.