The Straight Dope: Drug Addiction In The Civil War-"The Army Disease"
Drug addiction in the English-speaking world was rare at the beginning of the 19th century but common at the end of it, at least in the United States. By conservative estimate the U.S. had 200,000 addicts in 1900, with most of the increase occurring in the late 1800s. The Civil War is often blamed for this—after the war it’s said morphine addiction was widely known as “the army disease.”
Some historians think the war’s influence has been exaggerated and that “the army disease” is a fable concocted after the fact to justify repressive drugs laws. http://www.druglibrary.org/schaffer/History/soldis.htm.)
A major factor in the rise of drug use no doubt was the simple fact that more stuff became available as scientists explored the wonders of drug chemistry. Morphine, for example, was first synthesized in 1803, cocaine in 1859.
Still, even allowing for exaggeration by drug alarmists, you have to think the Civil War had some impact. Narcotics were handed out like candy by army surgeons, who were surrounded by suffering and had few remedies to offer other than painkillers. Nearly ten million opium pills were issued to Union soldiers, along with 2.8 million ounces of other opium preparations; no doubt opium use was fairly common on the Confederate side, too. One doctor reported keeping a wad of “blue mass” (a powdered mercury compound) in one pocket and a ball of opium in the other. He’d ask soldiers, “How are your bowels?” If the answer was “open” (due to diarrhea), the soldier got opium, if “closed” (presumably because of constipation), mercury. Opiates were used to treat not just wounds but chronic campaign diseases such as diarrhea, dysentery, and malaria. Narcotics became even more popular after the war as invalided veterans sought relief from constant pain.
That said, soldiers weren’t the only or even the major users of drugs, nor was drug abuse more prevalent in the Old West than in the rest of the country, as you suggest. On the contrary, casual use of hard drugs was widespread. Several surveys in the midwest in the latter 1800s found that the majority of opiate addicts were women who took drugs for neuralgia, morning sickness, or menstrual pain. Mary Chesnut, whose diary was read to haunting effect in Ken Burns’s Civil War documentary series, was a regular user. Narcotics could be found in the patent medicines of the day as well as in commonly prescribed medications like laudanum and paregoric, inexpensive opiates that could be ordered through the Sears catalog.