The risk of blood clots is heightened with the use of antipsychosis medication, according to study findings published online by the British Medical Journal.
Researchers discovered that people taking the medication, especially newer versions, had a bigger chance of having potentially fatal blood clots.
The study tested people taking older "typical" antipsychotics alongside newer "atypical" ones.
Atypical antipsychotics were produced in the 1990s.
The new research looked at data relating to around 25,000 people from 525 UK doctors' practices who had experienced blood clots. Of these, around 16,000 were marked as having had deep vein thrombosis and around 9,000 had had a pulmonary embolism (lung clot). A control group comprised around 90,000 people.
People who had been given antipsychotic drugs within the past two years were shown to be 32% more likely to have any type of blood clot. This increased risk was seen to double in patients who had only started taking one of the drugs in the past three months.
And those who were on atypical antipsychotic medication were nearly three times as likely to suffer a blood clot than those on conventional drugs.
Nonetheless, the overall risk of clots is small. Only four extra cases are estimated to arise in every 10,000 patients treated over one year. For over-65s, the estimated additional cases per 10,000 patients increased to 10.