There was a time, not so long ago, when in the popular imagination, a drug deal involved an aging hippie in a tie-dyed shirt and love beads, copping a joint at a Dead concert. Today, however, in the age of the Internet and smartphones, a teenager in his bedroom can select, order, and have delivered to his door illicit drugs via the marketplaces on the “dark web.”

As the name implies, the dark web is a subterranean layer of the Internet that is mysterious, ominous, and sometimes lawless. It lies “beneath” the surface web – the layer where grandmothers post on Facebook and purchase on Amazon.

The dark web largely was the brainchild of three mathematicians at the Naval Research Laboratory as a means of encrypting messages exchanged by the intelligence community. They dubbed their project “ Tor ,” for “The Onion Router,” as the system consists of layer after layer of random relays, permitting anonymity on the Internet with little risk of tracking or surveillance.

This online underworld first came to my attention several years ago. The father of a teen who was being treated for disruptive mood dysregulation, attention-deficit disorder, and alcohol and cannabis use disorder called to inform me that his son had been arrested at Lollapalooza with hundreds of Adderall tablets and Xanax bars. Several weeks later, in session, the young man disclosed to me that he had found simple instructions online about installing Tor, creating a VPN (a virtual private network), accessing the dark web, transacting with bitcoin, and identifying drug marketplaces. He also demonstrated a detailed knowledge of chemical manufacturing in China, pill pressing in Canada, and money laundering in Switzerland.

With the air of an insider sharing “trade secrets,” this young man described how dealers on the dark web avoid detection and ensure secure delivery of the goods: latex gloves, vacuum sealing, and bleach dipping to obviate fingerprints – human and chemical. He said that dealers will send “dummy” packages to throw off the authorities and that buyers often will use the address of a clueless or absent neighbor. In his case, however, the parcels were delivered to his doorstep.

To a generation raised on the Internet and virtual reality, buying drugs on the dark web can appear appealing and have many advantages. For one thing, acquiring drugs in this way can seem less risky, as there is no chance of being robbed at gunpoint in a sketchy neighborhood or being busted for possession during a routine traffic stop.

Crossing over to the world of the dark web also can give an adolescent a sense of being clever and rebellious and of pulling a “fast one” on the parents – and on us, the clinicians who are treating them. And a teen who is interested in using illicit substances and plays “ Call of Duty ” from the comfort of his family’s basement without actual injury or death might assume that he can attain illicit drugs that are safe and inexpensive.

There are counterarguments to misinformation about the dark web. For example, contrary to the notion that buying drugs on the dark web minimizes interdiction or arrest, clinicians should point out that since international law enforcement shut down Silk Road and incarcerated its founder, Ross Ulbricht (also known as “Dread Pirate Roberts”) in 2013, hundreds of other dark web marketplaces such as AlphaBay and Hansa have been silenced and their operators prosecuted.

Moreover, the U.S. Department of Justice recently launched the Joint Criminal Opioid Darknet Enforcement (J-CODE) group, and the U.S. Postal Service Inspection Service reportedly has been hiring cybercrime and dark web specialists to combat drug trafficking. It might come as a surprise to a teen that, in a state where recreational marijuana is legal, transport and delivery of cannabis by the postal service elevates purchase and possession to the level of a violation of federal law. Informing even the most oblivious or oppositional adolescent that a drug felony can disqualify him for college grants and loans, impede his search for gainful employment, or prohibit him from obtaining a professional license, might give him a moment’s pause.

Adolescents seeking to buy drugs on the dark web should brace themselves for another shock. Whether lulled by custom after years of shopping on Amazon or using PayPal, or simply dulled by addiction, they might have a blind trust that bitcoin tumblers and “dark” escrow accounts will secure their payments. It will be rude awakening when they learn that the transfer and holding of currency on the dark web is vulnerable to hackers and to operators of the marketplaces – who are known to simply abscond with funds.

Currently, the drug marketplaces on the dark web represent a thin slice of the total illicit drug trade. These marketplaces, however, are growing quickly and offer buyers a virtual smorgasbord: the leading prescription drugs bought are Xanax and OxyContin, whereas 3,4-methylenedioxymethamphetamine (MDMA)/ecstasy and cannabis are the most commonly purchased controlled Schedule I substances, according to an article in The Economist. The estimated annual sales for 2016 ranged from $100 million to $200 million, but even more alarming is the percentage of substance abusers who have purchased drugs on the dark web: A recent article in The Independent reported that 13.2% of U.S. respondents self-reported making at least one purchase online, whereas in the United Kingdom, the self-reported percentage was 25.3 %, and in Finland, it was 41.4%.

Evidence abounds that drugs purchased on the dark web often are counterfeit and sometimes “dirty.” There is a report of “Viagra” containing cement dust, of “Ambien” containing haloperidol, and “Xanax” laced with fentanyl, the latter having been linked to several deaths and hospital admissions in the Bay Area in 2016. (Big Pharma, in fact, is engaged in surveillance and investigation of the sale of knockoffs online, The Telegraph reported in article about the proliferation of fake drugs available on the surface web).Unfortunately, attempting to reduce teen substance abuse using law enforcement measures directed at dark web marketplaces might be a game of whack-a-mole: As soon as one supply source is staunched, another surfaces. Indeed, addiction should be viewed not simply in terms of the biopsychosocial model, but also as an economic activity. Thus, it might be more beneficial for clinicians to concentrate our resources and efforts on curtailing the demand through education and treatment.

As long as the ventral tegmentum and the nucleus accumbens reside deep in the brain, humans will be at risk of addiction. And as long as teenagers are vulnerable to peer pressure, impulsivity, early adversity, and other stressors, they will be at risk of addiction. In advising parents, in addition to encouraging ongoing, open, informed, and nonjudgmental discussions about substance abuse with their children, clinicians can suggest regular checking of passwords, browsing history, searches for information about the dark web (for example, Tor, VPN), and of use of P.O. boxes for Internet deliveries. And for mental health providers, the rise of the dark web is a stark reminder that we should inquire regularly about our clients’ substance use – and use of the Internet.

Dr. Marseille is a psychiatrist who works on the staff at a clinic in Winfield, Ill. His special interests include adolescent and addiction medicine, eating disorders, trauma, bipolar disorder, and the psychiatric manifestations of acute and chronic medical conditions.