Addicts get stuck emotionally at the age they first started using. So if they started using at 16 then emotionally they are a 16 yo when they quit.
That's assuming they were at age 16 emotionally when they started using. They frequently aren't.
A kid who grows up in a family where it's considered normal for people to not function at anything resembling an appropriate developmental level may be 16 years old chronologically, but have the reading or math skills of a 2nd-grader, the emotional regulation skills of a 5-year-old, the practical cleaning and elder or child care skills of a 30-year-old, the lie detection capability of a seasoned FBI interrogator, but the social skills and boundary awareness of a toddler. In families like these, kids are raised to be either future adult-shaped infants, or future enablers. Maybe both.
The 16 years the kid has lived chronologically have generally been in a very twisted, maladaptive environment. They didn't get 16 years of normal cause and effect, normal interpersonal interactions in which people respond appropriately to negative behavior, or normal boundaries and social expectations. Their reasons for choosing to use in the first place come partly from the twisted head space they develop, which is frequently nourished and reinforced by the people around them. When-- if-- the user emerges from the fog years later, gets away from the addictive practice, and decides to live, a whole lot of what they have to do is un
learning some of the bad logic, false assumptions, and messed up values that have made up their world view. A lot of what they knew, or thought they knew, is just plain wrong. They truly don't know what's right or what's normal.
Here's an example. Two imaginary 16-year-old high school girls are in the principal's office for dress code violations. Both are being written up and punished in some way. Both are embarrassed at having been singled out. But they react in very different ways.
Kid #1, raised in a normal cause and effect environment, understands she's in the office because of something she chose to wear. She knew the rules, chose not to follow them, and is experiencing a pretty predictable result even though she's gotten away with wearing similar clothing in the past. She also knows that when the punishment is over, it's over. So she sees no point in making the situation worse than it is. After the incident is over, she makes better choices about what to wear to school.
Kid #2, raised in an abnormal environment, understands she's in the office because her teacher is being an unreasonable bitch who's out to get her. She also knew the rules, but she truly doesn't believe they should apply to her or that there should be consequences for breaking them. She believes the rules are stupid and that people are wrong to impose them on her. Her belief in her moral rectitude is sincere, and it's also self defense. Since she's used to being hit or beaten for any action that displeases an adult, she has reason to believe that any mistake will not only result in a beating but will be held against her and thrown in her face for months or years. She therefore refuses to admit that she did anything wrong even though it's obvious her clothing violates the dress code. She searches desperately for reasons why it's not her fault: someone else bought her the clothing, or she got away with wearing it before so that's "proof" the rules aren't real. Meanwhile she doubles down on her bet by continuing to find and wear similar clothes in the future. These are necessary survival behaviors. Every time an authority figure fails to report the dress code violations, in her mind she "wins" because she sees proof she's right about why the rules don't matter and she doesn't have to follow them. Every time she gets called on the violation, in her mind she "wins" because she sees proof the people around her are wrong or unreasonable, therefore what she's doing is right and acceptable.
Now, suppose Kid #2, age 16, were to start using tomorrow. She wouldn't be frozen emotionally at age 16. She'd be frozen at the developmental level she has, with severely maladaptive behaviors. Her understanding of causality, marred as it is by magical thinking, is at about a 3-year-old's.
Fast-forward a couple decades, and Kid #1 and Kid #2 meet again at their high school reunion. Kid #2 has stepped away from her addictive practice but is less than a year sober. Kid #1 has a mainstream job, maybe a spouse and some kids. They decide to hang out a bit and get caught up. Is Kid #2 likely to make a strong hint that her friend ought to "lend" her money, or see anything wrong with going through her friend's purse to find and borrow some lipstick?