Automatism, in

toxicology Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating expo ...

, refers to a tendency to take a drug over and over again, forgetting each time that one has already taken the dose. This can lead to a cumulative overdose. A particular example is

barbiturates Barbiturates are a class of depressant drugs that are chemically derived from barbituric acid. They are effective when used medically as anxiolytics, hypnotics, and anticonvulsants, but have physical and psychological addiction potential as ...

which were once commonly used as

hypnotic Hypnotic (from Greek ''Hypnos'', sleep), or soporific drugs, commonly known as sleeping pills, are a class of (and umbrella term for) psychoactive drugs whose primary function is to induce sleep (or surgical anesthesiaWhen used in anesthesia ...

(sleep inducing) drugs. Among the current hypnotics,

benzodiazepines Benzodiazepines (BZD, BDZ, BZs), sometimes called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, i ...

, especially

midazolam Midazolam, sold under the brand name Versed among others, is a benzodiazepine medication used for anesthesia and procedural sedation, and to treat severe agitation. It works by inducing sleepiness, decreasing anxiety, and causing a loss of a ...

might show marked automatism, possibly through their intrinsic

anterograde amnesia In neurology, anterograde amnesia is the inability to create new memories after the event that caused amnesia, leading to a partial or complete inability to recall the recent past, while long-term memories from before the event remain intact. T ...

effect. Barbiturates are known to induce

hyperalgesia Hyperalgesia ( or ; 'hyper' from Greek ὑπέρ (huper, “over”), '-algesia' from Greek algos, ἄλγος (pain)) is an abnormally increased sensitivity to pain, which may be caused by damage to nociceptors or peripheral nerves and can ...

, i.e. aggravation of pain and for sleeplessness due to pain, if barbiturates are used, more pain and more disorientation would follow leading to drug automation and finally a "pseudo"suicide. Such reports dominated the medical literature of 1960s and 1970s; a reason replacing the barbiturates with benzodiazepines when they became available.Lexicon of Psychiatry, Neurology, and the Neurosciences by Frank J Ayd from Lippincott Williams & Wilkins, 2000

References

Toxicology {{med-toxic-stub