Schizophrenia is a life-long condition which's symptoms can be controlled through the use of antipsychotic medication. A study comparing two different schizophrenia medications has found that there are little differences in results from the two treatments. This information suggests that drug selection should be based on anticipated adverse effects rather than desired outcomes.

In the study researchers randomly assigned 311 patients diagnosed with schizophrenia or schizoaffective disorder to receive monthly injections of haloperidol decanoate or paliperidone palmitate for up to 2 years, as reported in a recent press release. Haldol decanoate is an older antipsychotic drug that costs about $35 per injection. It is most commonly used for the long-term treatment of schizophrenia; also it may be used for other condition as well. Haldol decanoate works by correcting a chemical imbalance in the brain. Paliperidone palmitate is a newer treatment option for schizophrenia that works similarly to Haldol decanoate by balancing cerebral chemicals. Paliperidone palmitate costs quite a lot more than Haldol decanoate, and can go for about $1,000 per injection.

Researchers then measured the efficacy failure rate, or the inability to produce a desired result, exhibited in patients on both medications. The criteria for an efficacy failure were defined as follows:

  • Psychiatric hospitalization
  • Need for crisis stabilization
  • A substantial increase in frequency of outpatient visits
  • A clinician’s decision to discontinue the medication due to inadequate therapeutic benefits

Results showed that the most common reason for an efficacy failure were psychiatric hospitalization and clinician discontinuation of medication. "The results [of this study] are consistent with previous research that has not found large differences in the effectiveness of newer and older antipsychotic medications," the authors concluded in the press release. What the researchers did find were quite sizable differences in side effect of the two medications. Patients prescribed paliperidone palmitate gained weight while patients taking haloperidol decanoate  lost weight. Also treatment with paliperidone palmitate often caused an increase in a hormone called serum prolactin. Patients prescribed haloperidol decanoate were found to exhibit akathisia, a type of movement disorder.

Finding the right medication is necessary to help schizophrenia patients control their often debilitating symptoms. Although it may be initially disappointing to learn that there are no large discrepancies in results following treatment with haloperidol decanoate or paliperidone palmitate, information from the study can be used to help patients select the best treatment option. "Setting aside the substantial differences in cost between haloperidol decanoate and paliperidone palmitate, the results from [this] trial suggest that drug selection should be based on anticipated adverse effects rather than efficacy," Donald C. Goff, M.D., of the New York University School of Medicine, and Associate Editor of JAMA, explained in the press release.

The study confirms that clozapine remains the only antipsychotic drug to produce clearly superior outcomes. Unfortunate clozapine can have extremely dangerous side effects such as seizures and swelling of the heart muscles. For this reason it is limited in use.

Schizophrenia alters an individual’s perception of reality. It is a largely misrepresented mental condition mared by misleading stereotypes.  “People are often labelled as ‘schizophrenic’ and there is an unhelpful association with homicide and violence in the media. This can worsen stigma and lead to people not engaging with treatment,”Dr. Martin Baggaley, medical direct at South London and Maudsleg NHS Foundation Trust, told The Independent.  New breakthroughs in our understanding of mental condition, such as a recent study which confirmed patients with schizophrenia have unique differences the physical appearance of their brains, aim to help researchers develop more effective treatment.  

Source: McEvoy JP, Byerly M, Hamer RM, et al. Effectiveness of Paliperidone Palmitate vs Haloperidol Decanoate for Maintenance Treatment of Schizophrenia :A Randomized Clinical Trial. JAMA. 2014