1. "Once an Addict, Always an Addict"
2. "Going Cold Turkey is the Only Way to Quit"
Again, this is an ignorant comment. Although quitting drugs and becoming abstinent overnight might seem like the best solution, giving up drugs suddenly can actually be one of the most difficult and dangerous ways to tackle an addiction. With some drugs, such as alcohol and benzodiazepines, going cold turkey can induce seizures and can even be life-threatening. With meth withdrawal, people can become delusional and violent if they suddenly withdraw from the drug. The best way to quit a drug is under medical supervision or in a detox facility.3. "It's Your Parents' Fault"
Drug addiction is a complex condition, and when someone develops an addiction, it's typically the result of the interplay between physical, psychological, and social vulnerabilities. While parents have a huge influence on whether someone becomes addicted to drugs — by role modelling unhealthy behaviors or being abusive, for example — this isn't the whole story. Some people with supportive parents still go on to develop drug problems, and many people with less-than-perfect parents do not go on to become addicted to drugs. Whether or not an individual's parents played a role in the development of her drug addiction, blaming the parents is unhelpful and hurtful.4. "Let's Go For a Drink — Alcohol is OK, Isn't it?"
Alcohol is a drug, and although it may be legal for adults, it's one of the most harmful and addictive drugs out there. Encouraging alcohol use will not help someone quit drugs, and may reduce his impulse control and increase feelings of depression afterwards, possibly increasing drug use. Bonding over alcohol also reinforces the belief that drugs are necessary for socializing with others. A more helpful way of supporting someone with a drug addiction is to accompany him in an activity that does not include any addictive substances or behaviors.5. "You Just Need to Pull Yourself Together"
If you've never struggled with an addiction or other psychological problem, such as anxiety or depression, you have no idea how difficult it can be for someone to make such a profound change to their way of coping with life. Yet people who haven't had significant problems in their lives often think that the problems of others are easily solved, and a simple matter of down-to-earth advice and will-power. In fact, the person with the drug addiction is probably well aware of what they "need" to do, whether it's to quit drugs, get a job, meet a partner, or any of the other goals that society imposes on people. Telling her to pull herself together is likely to come across as patronizing, and it may be undermining to her self esteem, which can lead to the person's seeking comfort in drug use. Instead of lecturing, help her "pull herself together" by supportive actions, and letting her know you care about her.6. --
Sources
Hser, Y., Evans, E., Huang, D., Brecht, M. and Li, L. "Comparing the dynamic course of heroin, cocaine, and methamphetamine use over 10 years." Addict Behav 33:1581-1598. 2008.
McGregor, C., Srisurapanont, M., Jittiwutikarn, J., Laobhripatr, S., Wongtan, T. & White, J. "The nature, time course and severity of methamphetamine withdrawal." Addiction. 100:1320-1329. 2005.
Zinberg, N. Drug, Set, and Setting: The Basis for Controlled Intoxicant Use. Yale University Press. 1986.


