Drugs are present as in-game consumables and come in inhalers, nasal rinses, patches, and srynges. In practise, they're all vapourized into a medicinal fog the PC huffs through an inhaler.
In addition to Nyoka, the player can become an alcoholic if they choose to take the flaw. There are several bars throughout the game that the player can visit, and the loading screens occasionally show ads for fictional alcoholic drinks. The plot for the Murder on Eridanos DLC heavily involves the launch of a new flavor of vodka, and the vodka distillery is a key location.
Mantisaur enemies are based off of giant praying mantises and their other life stages look like giant caterpillars or swarms of small insects. The main enemies of the Murder on Eridanos DLC are giant brightly-colored slugs.
A character makes a brief comment about his mother warning him that “marauders will violate you” but this is used to emphasise the mother’s overprotectiveness.
A sidequest on Monarch involving the C&P Boarst Factory heavily implies that the man running it has been eating his employees. Another sidequest on Monarch involves a family that lures people away from town to kill and eat them. The computer logs on an abandoned colony ship state that the crew resorted to eating some of the hibernating passengers.
Present in Peril on Gorgon in the Human Inquiry and Auditing building and the garbage disposal area, on par with the corpse depictions in the rest of the game. Present in Murder on Eridanos in the form of characters with parasitic slugs stuck to their neck and exaggerated grins.
The Peril on Gorgon DLC involves exploring a laboratory that was used for human experimentation. A character in the Murder on Eridanos DLC mentions torturing an employee as punishment, but doesn't describe the torture.
In the Peril on Gorgon DLC, a preserved eyeball found in a safe is used to open a retinal scan lock. The player has the option later to give the eyeball back to the person it was taken from.
It hugely depends on what you consider "excessive". It has about the same amount as similar games (such as the later entries in the Fallout series) would have. I would exercise caution if you are upset by gore.
Either Phineas Welles or Sophia Akande is kidnapped and held hostage in the game's final dungeon, depending on which one of them the player chose to side with.
Characters reference vomiting and some NPCs make retching noises. Parasite-infested enemies in the Murder on Eridanos DLC occasionally vomit or spit bright purple goo as an attack.
The Groundbreaker colony ship has a large hospital-style infirmary that the player can explore and is involved in two sidequests. Other locations have smaller infirmaries that the player can visit.
The Peril on Gorgon DLC is centered around the development of a dangerous experimental stimulant drug that was found to cause brain damage and violent behavior after regular use. Victims of the drug can be fought throughout the game world.
An early sidequest involves several deaths that happened prior to the start of the game, one of which was a suicide.
Anton Crane of Roseway can potentially commit suicide off-screen with an audible gunshot after you turn in his quest, if the player unlocks the dialog option and passes a persuasion skill check to tell him that he's beyond redemption.
A sidequest on Groundbreaker to investigate an abandoned space station ends with discovering that its last inhabitant committed suicide some time ago.
If the player decides to side with the Board instead of Phineas, choosing harsh dialog options while talking to Phineas at the end of the game can potentially lead him to committing suicide on-screen.