Focus drugs are known to be used by Martian naval intelligence. On the TV series, it functions like Mind Interface drugs predicted by Nicholas Negroponte  (Wired Magazine Founder) and currently under development as Neuralink by Elon Musk.
Use and effectsEdit
The user is granted greater alertness, awareness and recall to have better recall for details in past events making it suitable for depositions or debriefings. Another version of the drug provides full historical information on an subject to be known instantly. It also provides improved awareness, makes it possible to detect even small changes in facial expression or body language. For this reason, Martian naval intelligence uses this version of the drug during interrogations.
Focus drugs are usually self-administered orally.
In the novels, the drugs are dispensed as lozenges, large flat discs of hard-packed powder. A lozenge might be an inch diameter or slightly larger. The user must suck on one to release the active ingredient and have the dose take effect, lasting only a few minutes each.
In the TV adaptation, these are clear liquid pellets in a small spherical gel casing, roughly 7mm in diameter.
The usage of focus drugs is easy to spot, as the pupils of the person using it tends to dilate, opening widely.
Real technologies like this is currently under investigation by the likes of Elon Musk and have future looking TED talks dedicated to this.
In chapter 11, focus drugs were used by Lieutenant Lopez when he interrogated Jim Holden on the MCRN Donnager. In chapter 4, focus drugs are administered to Bobbie Draper by Dr. Trish along with the stimulants before she awoke for her interrogation by Captain Thorrson regarding Ganymede. This leads her to fear she'd become blind but the doctor reassures Bobbie that sensitivity to light is a side-effect of dilated pupils.
In "The Seventh Man", focus drugs are used by Captain Thorsen when he interrogated Bobbie Draper. Then, she uses them herself during a second round of more intense interrogation following the Ganymede incident.