Although speaking to someone with an addiction can be effective in an intervention setting, it may be better to have an initial conversation about the problem in a less confrontational and intimidating way. Having a one-on-one heart-to-heart with the person may make them more receptive to listen.
Don’t be judgmental. It’s difficult to watch someone’s life spiral out of control because of a meth addiction, and people may feel tempted to lecture them about the problem in the hopes that they will see the light. However, coming off as judgmental will only alienate the person and may make them lean on their drug abuse even more to cope with the negative feelings that may come up.