Is there a way to get my OTH to be changed to Honorable?

SN Tom Yocum You could request a review and upgrade; but it will only be considered if there was a mistake in the discharge. If you in fact where properly discharged due to drugs and alcohol in '85; there is nothing to correct. You would have to proved that at the time of discharge you were separated under false or incorrect terms. Best of luck to you

SN Tom Yocum The only way to get that changed I believe is through the Navy Discharge Review Board. Best of luck to you. That's a big jump from Other than Honorable to Honorable. You will be lucky to get it raised to General Under Honorable Conditions.

You need to start at the Navy Discharge Review Board.
A couple of things not in your favor. First is there is a 15 year statute of limitation on requesting a change and you are past that time frame. There are some exceptions these days, discharge under DADT, you have a TBI, or Sexual Assault.
Since you didn't say you were innocent, I will point out that the Discharge Review Board is normally about correcting mistakes and yours doesn't appear to be a mistake.
Still, the worst that can happen is you get turned down and that isn't any different than where you are today.