This week’s Elementary will explore the darker days of Sherlock’s addiction. But what do we already know about the detective’s past indulgences?

Elementary takes the modern Sherlock Holmes and puts the darker days of his addiction in the past. As viewers we are not privy to the man Sherlock once was in London. So far we have only seen the man Sherlock Holmes has become after he put his demons to rest.

We’re not dealing with a man hiding one addiction, but one who is building a life beyond the dependency of the drugs he used to call on to numb the nerve endings. The occasional boost of endorphins received from being in the thick of a case replaces those urges now, but what else do we know about his life before? This week, Elementary pokes at the man Sherlock has a done a great deal of work to separate himself from.

1. Sherlock’s drug use started as a casual habit

Sherlock’s sobriety meetings shed some light on the detective’s reasoning for partaking in drugs in the first place. Week in and week out we are reminded of Sherlock’s uncanny sense of smell and attention to detail. Before he had the partnership of Joan Watson, Sherlock took the occasional dose of illegal substances to bounce around ideas and draw those meaningful connections.

2. Sherlock’s support system

Sherlock shows no signs of having any meaningful relationships in London. Apart from his relationship with Irene, Sherlock was not a favorite of Scotland Yard, nor did he greet his family with open arms. Through his recovery, Sherlock has not only explored those past relationships and made amends where they were needed, but he has gone one step further and built more than one valuable connection. Joan Watson is the obvious name that comes to mind, but Captain Gregson, Detective Bell, and Kitty Winter each mean a great deal to the man he has become in the present. Whether or not he is willing to vocalize his appreciation is another matter all together.

3. He may be sober, but not free

When you work on NYPD homicide cases the likelihood of crossing paths with drugs is not out of the question. Sherlock has run into drug related cases, had cocaine tossed to him by a former friend, and even held onto a bit to test himself. The temptation will always be around him, but the clarity of his mind without the drugs and the meaningful relationships seem to be enough to curb his interest. For now…

4. Sherlock replaces his need for drugs with other stimulants

The absence of drugs in Sherlock’s life is no great loss for anyone. But what does Sherlock turn towards when the mental blocks arrive and the NYPD is not calling fast enough? There are the old standbys – starting conspiracy theories online, practicing singlestick, ballistic tests. Physical exercise also plays a role increasing blood flow to the brain. But when his mind becomes too clear is when you really have to worry about the detective. Now that Joan and Kitty’s training exercises no longer present Sherlock with dollhouses to paint with blood, the sky is the limit for new things he may try.

5. Irene’s death was the catalyst for destruction

Obsession got the best of Sherlock Holmes in London as he searched high and low for Irene’s killer. But when dead end after dead end broke his hope down, Sherlock turned to drugs to keep him going and simultaneously dull the pain. It was this event that lead Sherlock into rehab, and this instance that keeps him grounded in the reality that even he can be susceptible to trickery at the hands of a mastermind.

While he may be able to separate his past self from his present self, they are always going to be entwined. He does not want Joan to meet the man he was on drugs, the man he is not even sure he knew.

Watch Elementary season 3, episode 16, “For All You Know,” Thursday, March 5 at 10:00 p.m. ET on CBS.