Notions of mental illness are, by and large, cultural in nature. One country's disorder is another country's socially acceptable behavior. In no case is this clearer than in the way in which alcohol is regarded in Japan as compared to western cultures. Outside of missionaries or Christian-related treatment programs, alcoholism as a disease does not exist in Japan for all practical purposes.
That is not to say that there are no Japanese people who are dependent on alcohol to cope with the difficulties of life nor those who would have a great deal of difficulty stopping their drinking. It is, by and large, the case that people who use alcohol to cope are not seen as having a problem. Drinking is such an important part of Japanese social culture that it'd be very hard to separate getting loaded and blowing off steam after work as a socially-sanctioned therapeutic choice from being a dangerous addiction to alcohol.
This is a fact that is constantly brought home to me any time the topic of drugs is discussed with Japanese people. Every person I have ever spoken with seems to fully believe that all drugs, from marijuana to heroin, are equally destructive and addictive. In fact, it's shocking how little factual information they have about cannabis smoking. It seems as if they've been shown "Reefer Madness" about a hundred times and embraced every word of it as scientific proof of the horrors of weed usage. Most seem to have no idea about the true effects of illegal, recreational drugs. Of course, many don't have any idea of the true effects of legal, prescription drugs either. This is one of the reasons birth control pill usage is so low. Doctors tell horror stories about their side effects to dissuade people from using them.
It isn't necessarily a shock that the Japanese are misinformed about drugs since all cultures are (at times) exposed to propaganda which they swallow whole depending on the zeitgeist it is presented in. The U.S. has been exposed to some pretty shaky proclamations in regards to security and people have been believing it since 9/11. You can get people to believe a lot of wild notions if they are fearful enough.
What is more shocking is the ignorance and lack of concern the Japanese have for alcohol and its effects. A student I spoke with this morning proclaimed that drugs were very bad for your health but alcohol had no ill effect on one's body. Given this, she felt it was fine that she drinks to relax. To be honest, I'm certain this student has had a drink on occasion before her lessons with me as I've smelled it on her breath on a few occasions. If this doesn't sound like such a big deal, keep in mind her scheduled lesson time is noon on a weekend day. When I told her that drinking alcohol kills brain cells and damages the liver, she had no idea that alcohol had such effects.
The situation in Japan regarding drugs and alcohol demonstrates something one doesn't often see when one does not stray outside one's native culture. That is the fact that all the information you get from your country's native scientific and media sources is skewed to suit the particular biases and prejudices of your culture. If your culture wishes to convince you one thing is bad and another is innocuous, it will tend to showcase evidence that supports this notion. If you look hard enough, you may find both are equally bad or innocuous but tend to reject that information because you agree with the bias and have a vested interest in believing what you want to believe is true rather than accepting objectively-obtained facts.
In the case of the U.S., this situation is best illustrated by the way marijuana tends to be regarded by non-users. European countries which have legalized pot would lend support to the idea that it isn't a horrific drug which will lead you down a path to harder drugs and a life of fuzzy-headed preoccupation with finding munchies and slacking off, but Americans tend to reject information that comes from outside their own country. On some level, I do wonder if all countries are aware of the bias applied to their conclusions but fail to discuss topics more objectively because they are comfortable with their bias and how it supports the rightness of their world-view.
For the record, I'm not endorsing marijuana consumption (or alcohol or anything). Personally, I've never consumed an alcoholic beverage nor used any sort of recreational drug and have no basis from which to draw conclusions other than experiences related to me by others and information I've read.