Patients with schizophrenia are often treated with more than one type of psychiatric medication, but a new study suggests that some combinations may be more effective than others. The findings were published in JAMA Psychiatry.

Antipsychotic drugs are usually the first line of treatment for individuals with schizophrenia. But because these drugs often fail to control symptoms adequately on their own, doctors often prescribe additional psychiatric medications, such as another antipsychotic, an antidepressant, a benzodiazepine, or a mood stabilizer.

"Antipsychotic medications are used to treat psychotic symptoms such as delusions and hallucinations, but there is little guidance on what to do for other types of symptoms like depression, anxiety, or excitement. Additional medications are often prescribed, but we know little about how different psychiatric drug combinations affect people with schizophrenia," says T. Scott Stroup, MD, MPH, professor of psychiatry at Columbia University Vagelos College of Physicians and Surgeons and lead author of the paper. "Until now we have known virtually nothing about how these strategies compare to each other."

To find out, the researchers conducted a comparative effectiveness study using Medicaid records of 81,921 adults with schizophrenia who had been taking only an antipsychotic drug for at least 3 months before starting either an antidepressant, benzodiazepine, mood stabilizer, or another antipsychotic drug.

The researchers found that individuals with schizophrenia who added an antidepressant were less likely to land in the emergency room or hospital for a mental health issue than those who started another antipsychotic or a benzodiazepine. Antidepressants reduced the risk of hospitalization by 16% compared to antipsychotics and by 22% compared to benzodiazepines. For emergency room visits, antidepressants reduced the risk by 8% compared to antipsychotics and by 18% compared to benzodiazepines.

"Our study adds more evidence that benzodiazepine use should be limited and that combining antidepressants with antipsychotic drugs for individuals with schizophrenia may have benefits," says Stroup. "We still need to know more about when to use antidepressants, which may be useful for conditions other than depression."

Combining medications is often referred to as polypharmacy. "The results of our study should promote rational polypharmacy," added Stroup. He thinks that clinicians will find the results believable and hopes that they will lead to practice changes and improved patient outcomes. The study is titled, "Comparative Effectiveness of Adjunctive Psychotropic Medications in Patients with Schizophrenia."