I’ve known about “aging out” for ages, but former addict and neuroscience journalist Maia Szalavitz eloquently boils down the evidence:

According to the American Society of Addiction Medicine, addiction
is “a primary, chronic disease of brain reward, motivation, memory, and
related circuitry.” However, that’s not what the epidemiology of the
disorder suggests. By age 35, half of all people who qualified for
active alcoholism or addiction diagnoses during their teens and 20s no longer do, according to a study of over 42,000 Americans in a sample designed to represent the adult population.

The average cocaine addiction lasts four years, the average marijuana
addiction lasts six years, and the average alcohol addiction is resolved within 15 years. Heroin addictions tend to last as long as alcoholism, but prescription opioid problems, on average, last five years.
In these large samples, which are drawn from the general population,
only a quarter of people who recover have ever sought assistance in
doing so (including via 12-step programs). This actually makes addictions the psychiatric disorder with the highest odds of recovery.

While some addictions clearly do take a chronic course, this data, which replicates earlier research,
suggests that many do not. And this remains true even for people like
me, who have used drugs in such high, frequent doses and in such a
compulsive fashion that it is hard to argue that we “weren’t really
addicted.” I don’t know many non-addicts who shoot up 40 times a day,
get suspended from college for dealing, and spend several months in a
methadone program.

She continues:

Moreover, if addiction were truly a progressive disease, the data
should show that the odds of quitting get worse over time. In fact, they
remain the same on an annual basis, which means that as people get
older, a higher and higher percentage wind up in recovery. If your
addiction really is “doing push-ups” while you sit in AA meetings, it
should get harder, not easier, to quit over time. (This is not an
argument in favor of relapsing; it simply means that your odds of
recovery actually get better with age!)

So why do so many people still see addiction as hopeless? One reason
is a phenomenon known as “the clinician’s error,” which could also be
known as the “journalist’s error” because it is so frequently replicated
in reporting on drugs. That is, journalists and rehabs tend to see the
extremes: Given the expensive and often harsh nature of treatment, if
you can quit on your own you probably will. And it will be hard for
journalists or treatment providers to find you.

Similarly, if your only knowledge of alcohol came from working in an ER on Saturday nights, you might start thinking that prohibition is a good idea.
All you would see are overdoses, DTs (delirium tremens), or car crash,
rape, or assault victims. You wouldn’t be aware of the patients whose
alcohol use wasn’t causing problems. And so, although the overwhelming
majority of alcohol users drink responsibly, your “clinical” picture of
what the drug does would be distorted by the source of your sample of

Treatment providers get a similarly skewed view of addicts: The
people who keep coming back aren’t typical–they’re simply the ones who
need the most help. Basing your concept of addiction only on people who
chronically relapse creates an overly pessimistic picture.

Szalavitz does not discuss the equally fascinating “contingency management” literature that documents the strong effect of incentives on substance abuse.  But both bodies of evidence point in the same Szaszian direction: despite addicts’ self-serving excuses, addiction is a choice – a choice to be immature.