ABC's Elementary and Sherlock Holmes's abnormal addiction

Sherlock Holmes is addicted to cocaine in the Sign of Four.
He claims that he uses merely for a "mental stimulant," which is
probably partially true given Sherlock's unusual psyche.
ABC's Elementary portrays Sherlock in a similar way: he's a recovering
addict who manages to stop drugs cold turkey, mostly from his father's
behest.
The show uses drugs and medical imagery extensively in the development
of Sherlock's character.
Dr. Watson, the voice of reason for Sherlock, is an ex-surgeon and
Sherlock's sober companion, meaning that the theme of Watson's Sign of
Four speech---asking Sherlock to care for his health---is repeated
throughout the series.
She puts the focus squarely on Sherlock's internal struggle with a past
that he wants to hide.
This manifests in some of Sherlock's unhealthy habits like refusing to
sleep until a case is solved or refusing to play his violin or being
mentally absent at group therapy meetings.
Mental health, a subject mostly untouched by Doyle, is a common theme of
Elementary.

[IMAGE: Low-Resolution Elementary Title, CAPTION: Elementary studies
Sherlock's ups and downs in terms of his habits and treatment of others,
SRC: https://upload.wikimedia.org/wikipedia/en/6/69/
Elementary_intertitle.png]

But Elementary also tells stories about physiological health.
Like in The Sign of Four, Elementary's Sherlock follows storylines with
poisoning and medical elements.
Drugs are often the crux of the medical stories Sherlock investigates: a
heroin poisoning of a bank's executive meant to frame it as an overdose
hints at the social elements of addiction and health.
The Sign of Four also handles the social elements of health: both Major
Sholto and Captain Morstan die in events directly connected to thefts of
the treasure, and the original Sign of Four plan was motivated by
Sholto's self-inflicted poverty (gambling addiction).
The framing of both stories in Sherlock's cocaine "addiction" (I use
quotes here because it isn't exactly portrayed as such) clarifies health
as a social image because Sherlock is mostly treated as well by his
peers, being judged by the quality of his work in either story---the
image of unhealthfulness brought on by cocaine isolated as a possible
danger rather than a factor determining health on its own.

[IMAGE: Cocaine Toothache Drops ad, CAPTION: At the time the original
Sherlock Holmes stories were written, the negative effects of drugs were
neglected by doctors, but even in modern depictions Sherlock appears as
sane and healthy despite vice, SRC: https://upload.wikimedia.org
/wikipedia/commons/9/99/Cocaine_tooth_drops.png]