First, at least in my experience, far more beggars are alcoholics than drug addicts. This might vary in cities with heroin ‘epidemics’, but I rarely see homeless people who seem to be heroin or crack users. Some, especially those who sell newspapers instead of asking for money directly, are not alcoholics or drug addicts. They may have become homeless as a result of a bad financial situation, or a mental illness.
Integrating many of these people into the workforce is a well-meaning but unrealistic goal. Giving them a low-paying, unrewarding job with an abusive manager will not make them happier than they were when they were homeless, and it’s likely that they will not keep the job for long. For those with addictions, it’s important to realize that it is extremely difficult to treat addictions successfully, especially when the person is uncooperative.
Street youth are a different category; they’ve become homeless because of a situation at home, rather than a financial situation. For some, it might be physical or emotional abuse, an incompetent (and perhaps drug-or-alcohol-addicted) parent. Many street youth use alcohol and ‘soft’ drugs. Most areas have extensive programs for street youth, so if you’re concerned about this issue, you might want to contribute to one of the programs instead of giving money directly. (Except that street youth have a way of diverting donations from these programs for recreational purposes.)
Again, if you give money to a beggar, it’s far more likely that the money will be spent on alcohol than on crack or heroin. It is also very unlikely that an addict will rob or steal if they don’t make enough by panhandling. With heroin, at least, the drug itself discourages violence, and the addiction is not terribly expensive to maintain. Crack is different, but I don’t think crack users generally become panhandlers; I think they’re more likely to support their habit through crime in the first place, and not bother with panhandling.
Two more issues: food and withdrawal. Food is widely available to homeless people through shelters and soup kitchens. (Even for those who don’t stay in shelters because of the risk of having things stolen or getting diseases, it’s possible to eat at one without sleeping there.) Homeless people can get adequate food without panhandling. I’ve rarely seen them buy food; when I do see them in a fast-food place, they tend to not to buy food. They usually buy coffee, so they can sit inside and warm up. Finally, withdrawal is rarely fatal, and is only fatal for a very few drugs. A heroin addict will not die within hours or days if they don’t get heroin. They will get sick, but not die. IIRC benzodiazepines (and by extension probably alcohol) and barbiturates can be fatal.
ElectricZ: Don’t generally believe any story a homeless-looking person gives you; if they say they need money to get to a job interview, it’s really just a way of increasing appeal. I once saw someone begging in a business area with a ‘need job interview clothes’ sign. Homeless shelters will help with job interviews. They will provide bus fare to get to an interview. (Street youth here often try to sell transit tokens. I found out that they get tokens for going to job interviews, and so they often set up fake interviews and sell the tokens they get.) There are also organizations that will give low-income people business clothes for job interviews. If someone tries this line on you again, you might just want to tell them about that.