You know, like possibly cause you to have kids with genetic issues or mess up your own DNA codes? Or is this a myth? And I'm talking about a person who once abused drugs, but doesn't anymore. I just wanna know if it has an effect.
It doesn't alter your DNA. It can turn certain genes on or off though, most likely those associated with addictive behavior. It CAN mess up your reproductive system in both men and women, and make it more likely that your child will be born with a birth defect or unhealthy, probably how the rumor got started. However DNA itself will remain unaffected.
Can drugs alter DNA? Well, it sort of depends. Most drugs do not alter the DNA itself but alter its expression (i. e. how the DNA is transcribed and translated). Look up "drugs and epigenetics". That should help explain how drugs alter genetic expression. However, some drugs can actually induce DNA mutations to occur (thus actually altering the DNA itself). By the way, don't believe some of the other repliers who say that DNA cannot be altered. That is absolutely not true. DNA is actually a lot more dynamic than a lot of people seem to realize. Our DNA is constantly being mutated (either by our cells screwing up or by exposure to radiation, UV light, pathogens, etc.). Normally, our cells repair the damage and we continue to be in good shape. Cells that are too damaged end up killing themselves (apoptosis). The danger occurs when damaged cells refuse to kill themselves and instead divide. This can result in tumors and cancer. So yes, at the end of the day, there are certainly some drugs that are mutagenic (induce genetic mutations). I'm getting my master's in biology so I know I'm right lol :).
Not exactly. Altering DNA is what they work on in gene therapy, and it's not well-established yet, but environmental factors can affect gene *expression*. It's about the function of the gene though, not changing the DNA itself - meaning some genes can be turned on and off depending on which environmental factors you're exposed to.
Like a lightbulb. You don't change the switch, but you can turn it on and off. It's an area in science called epigenetics. There's been more research on how diet can affect gene expression, for instance. I'm uncertain which drugs, if any, have that kind of effect.