New findings from a long-term international study reveal the effects of lifetime exposure to several medications commonly used in schizophrenia, including antipsychotics, benzodiazepines, and antidepressants.
The research found that long-term, high-dose use of antipsychotic drugs is associated with poorer cognition in patients with schizophrenia; those who were able to take a relatively long break from antipsychotics had fewer cognitive problems.
On the other hand, low cumulative exposure to benzodiazepines, antidepressants, and antipsychotic medications did not appear to impact cognition in schizophrenia.
Schizophrenia is considered a lifelong condition, requiring long-term treatment and rehabilitation and long-term use of antipsychotic medication. However, drug trials are usually of short duration — for example, antipsychotic trials only last two to three years at most. Since many schizophrenia medications are used over long periods of time and may lead to significant side-effects, it is important to fully understand their long-term impact.
Researchers from the University of Oulu in Finland and the University of Cambridge in the UK presented observational data on the long-term use of psychiatric drugs in schizophrenia at the European College of Neuropsychopharmacology (ECNP) conference in Paris.
The study followed participants from the Northern Finnish Birth Cohort 1966 (all of the participants had been born in 1966). A total of 60 individuals had been diagnosed with a schizophrenia spectrum disorder and had received different medications over the long-term. The participants completed an extensive series of cognitive tests when they were 43 years old — at that point, they had been using medication for an average of 16.5 years.
The findings show that modest long-term use of common psychiatric medications, benzodiazepines and antidepressants had no noticeable effect on cognition. However, they contrast this with their previous finding (reported in January 2017) that the high-dose use of antipsychotic drugs was linked to poorer cognition in the long-term, by reporting that long breaks in antipsychotic treatment seems to result in better cognitive functioning.
“These are mixed results, which show different outcomes,” said lead researcher, Anja Hulkko M.D. at the University of Oulu. “Firstly, low long-term use of benzodiazepines and antidepressants doesn’t seem to have adverse effects on cognition in patients with schizophrenia.”
“These are not the primary medicine prescribed to people with schizophrenia to target psychotic symptoms. If there is little if any cognitive harm in using them with small doses or for short periods of time, then they may be promoted for anxiety, depression, or sleeplessness, which can be undertreated.”
“It should be noted that, high-dose long-term use of benzodiazepines has been associated with poorer cognition and according to treatment recommendations should be avoided.”
The new findings reinforce the team’s research published earlier this year on long-term high-dose antipsychotic use, by showing that long breaks in antipsychotic treatment right before neuropsychological assessment may be linked to better cognitive functioning in schizophrenia.
Schizophrenia patients with more severe illness are often prescribed higher doses of antipsychotics and those with milder illness may manage longer periods of time with smaller doses or even without antipsychotic treatment.
The researchers note that patients should continue to take antipsychotic medications as prescribed, as stopping treatment can lead to severe consequences. But it is also important that patients work with their doctors to find the minimum effective dose for the long-term, and perhaps consider psychosocial treatments and cognitive rehabilitation.
The findings are published in the peer-reviewed journal European Psychiatry.