But even for most doctors, the suggestion that Michael Jackson may have become addicted to the anaesthetic propofol, was surprising. It's not something one generally hears about, though other forms of addiction abound. Though it seems rare, it is recognised and reported, mainly among the anaesthetic community. This is not be due to any particular vulnerability among our sleep-inducing pals, but simply because ready access to the drug, and thus opportunities to develop such problems, are rare and largely limited.
Some experience of abuse of propofol (not necessarily the same thing as addiction) have been described, especially among doctors, and particularly within anaesthetics training programmes. I make the distinction because while these may be examples of psychological dependency, some of the other physical manifestations of a true addiction are not being described.
In one report on 25 people abusing Propofol, 7 died, 8 of them medical residents. This seems to be an effect of access to the drug, rather than any other risk factor. They seem to begin abusing it to self-treat insomnia caused by a range of factors.
A puzzle is what it is that attracts people to propofol abuse, especially considering that it generally induces amnesia. It is apparently uncomfortable on injection, causing a painful burning sensation by irritation, and for this reason is often combined with the local anaesthetic Lidocaine. But the amnesia would not help one remember that - it is presumably some of the benefits after waking, that make people want to repeat it.
Abusers describe more than sleep, but also a feeling of euphoria on awakening from the dose. There are some reports that the coma it causes may to some extent reduce the sense of sleep deprivation in the user, and leave the user feeling unusually refreshed and rested. As with other drugs of addiction, there can be an agreeable sense of relief, which is short-lived, and thus sought repeatedly. Some have commented on its abuse in patients with severe trauma-related insomnia and PTSD.
There have been studies in animals showing that it can cause an increase of dopamine in the areas of brain where a similar dopamine boost occurs in other addictions, so a possibility of addiction is at least plausible.
Some small studies have suggested that people with a previous history of drug abuse may like something about propofol, preferring it to a control when they have an opportunity to use it. This can be considered an ominous sign. Years back when we were doing research on a new tranquilliser as an alternative to the often abused benzodiazepines, it was reassuring to find that it was really unpopular with current drug addicts, who complained that it was useless to them: in one case a research subject even returned it after stealing a bunch of drugs from a pharmacy.
Considering the dangers of the drug when improperly used, it's perhaps surprising that it is not more carefully controlled as are other drugs of potential hazard. Perhaps when the Michael Jackson case is over, the authorities might tighten up controls on this possibly lethal drug.
(Professor M.A. Simpson, psychiatrist, Health24, October 2011)