Is there an age in which drug addiction will cause the most problems?

Early age onset: Drug addiction starting in early adolescence seems to have longer lasting and more hard to treat version. This is a time when your brain is maturing and drugs interfere with the development of complex psychological and physical changes.

<25 years: We haven't found any statistically significant way to predict a person's success in recovery from addiction, although certain activities seem to increase your odds at any age: things like compliance with medications, having a support group, avoiding triggers, etc. Generally, addiction that occurs before the brain is fully developed (age 22 in women, 25 in men) tends to have a worse prognosis.