Schizos Are Dangerous

Dr. James Thompson writes:

As you can see, assaults are committed by 1 in 7 untreated schizophrenics and by 1 in 10 treated schizophrenic patients per year. Treatment is only moderately effective in this regard. These are very high rates compared to the general public. Even with a relatively weak predictor, you need to monitor only 2 or 3 patients to possibly prevent an assault. This would be a highly effective intervention, and should receive more publicity. Large et al. seem to be doubtful about the value of screening in general, but their own data show it has utility for assaults.

For violent crime, monitoring 26 patients is required for a possible prevention of a violent crime. Again, this is manageable given resources.

Homicide in untreated patients happens, according to this table, at the very high rate of 1 in 600 schizophrenics. That compares with homicide rates in the UK of 0.9 per 100,000 persons and in the US of 3.9 per 100,000 persons. (US 4 times as murderous as the UK). So, the rate of homicide in non-schizophrenics in the UK is 1 in 111,111 and in the US is 1 in 25,641 persons. Therefore, an untreated schizophrenic person, using the estimates given in this paper, is apparently about 42 times more likely to murder someone than a US citizen, and 185 times more likely to murder someone than a UK citizen. Can these figures be correct? If so, this is a very dangerous category of person. An instrument with a positive predictive value of 0.66% (extremely low) requires that 151 persons be monitored. This would be onerous, but would prevent a murder. It is an indicator of the level of risk to the population when patients do not take their medication.

A homicide committed by a treated patient (1 in 10,000) means that treated schizophrenics are apparently 11 times more dangerous than UK citizens and almost 4 times more dangerous than US citizens. In the US it requires 2500 patients being monitored, a high number, and the best estimate of how difficult it would be to prevent one person being murdered, assuming most patients comply with treatment. Monitoring for most patients would probably involve no more than chasing up non-attenders at follow-ups, and doing some random checks on compliance with medication. This would be worth studying, particularly now that monitoring in diabetes is being trialled using mobile phone apps, with good results.

Here are a few reflections. Risk estimates vary considerably, but all are raised for schizophrenics, particularly in the early untreated phase. By implication, a schizophrenic patient who does not comply with medication falls into a high risk category. It seems very worth-while to screen for assaults, violent crime and homicide, particularly in untreated or medication-refusing schizophrenics.