Advancing medical knowledge using nonhuman primate research

Zared O.
United States


Demonstrators at a university protesting for and against animal research. Courtesy of the UCLA Bruin, Alexis Chavarria.

One of the most controversial areas in research is the use of nonhuman primates for experiments. Two decades ago, many animal rights activists thought that the use of nonhuman primates would become obsolete by the early 2020’s; yet, that has not been the case. Over the past several years, the use has actually risen, to over 75,000 per year.

For the past two summers I have been working in a lab helping physicians and scientists conduct research on one of the most pressing medical problems facing humanity. This is one of the leading causes of disability in the world, involving a subjective experience difficult to measure in lower animals, and is in the news nearly every day. Many labs studying advanced animals are shrouded in secrecy over concerns about negative publicity, protests, and even physical safety.1

As a low-level researcher, my job is to review hundreds of hours of videos of monkeys and record how often they exhibit certain behaviors. Some examples include increased vigilance and fear to indicate anxiety; changes in appetite and sleep as a surrogate for depression; food-vs-drug choices and drug self-administration to signify addiction; and self-injurious behavior, scratching, and grimacing to estimate pain.2-4 We give the monkeys various medications to see whether they have an effect on how often they demonstrate these behaviors, which we then assume is equivalent to the subjective experience we are actually trying to evaluate. During my time spent in the lab, I learned that this is one reason why only a tiny percentage of drugs for conditions such as anxiety, pain, and depression that work in animals prove effective in studies done on people.5-7 To reduce this failure rate, many scientists feel that performing studies on nonhuman primates, which share about 99% of our human DNA, is the best option. But it is also the most controversial.

While watching videos for hours each day, I came to realize that the monkeys we used were not like the rodents used for laboratory research. They can establish social bonds, exhibit emotions such as sorrow and happiness, and even can experience jealousy and anger.8 Before I started volunteering in the lab, I had to take some online courses on research. One point repeatedly made was that it was unethical to carry out experiments on prisoners and other persons who could not provide true informed consent. I began to wonder whether performing experiments in nonhuman primates is something that future generations may look back upon as the “dark ages” of medical research.

The justification for nonhuman primate research is that the findings cannot be generalized from lesser species and that it may improve the lives of humans. Although nonhuman primate research has led to some major breakthroughs that might never have been realized if the research had been carried out in lesser species, it is not universally accepted that the results of the experiments are always more generalizable to people.9

Many of the limitations of studying subjective conditions such as addiction, pain, and psychiatric illnesses in rodents hold true for monkeys, and the poor translation of animal studies to people raises questions about the necessity of nonhuman primate research. Nonhuman primates should only be used when lesser animals will not suffice, and when the anticipated benefits to people clearly and overwhelmingly outweigh the risks and suffering of the animals. I do realize that I may be too young to grasp the nuances of the entire picture but in my mind I have come to believe the work we do is justified because committees that oversee our research mandate that we use only the animals that we need to, and that we subject them to as little harm as possible. And even a relatively low success rate of animal research translating to people could potentially alleviate untold suffering and save tens of millions of lives.



  1. No authors listed. Inhumane treatment of nonhuman primate researchers. Nat Neurosci. 2015; 18: 787.
  2. Worlein JM. Nonhuman primate models of depression: Effects of early experience and stress. ILAR J 2014; 55: 259–73.
  3. Coleman K, Pierre PJ. Assessing anxiety in nonhuman primates. ILAR J 2014; 55: 333–46.
  4. Banks ML, Czoty PW, Negus SS. Utility of nonhuman primates in substance use disorders research. ILAR J 2017; 58: 202-15
  5. Akhtar A. The flaws and human harms of animal experimentation. Camb Q Health Ethics 2015; 24: 407-19.
  6. Belzung C. Innovative drugs to treat depression: did animal models fail to be predictive or did clinical trials fail to detect effects? Neuropsychopharmacology 2014; 39:041-51.
  7. Percie du Sert N, Rice AS. Improving the translation of analgesic drugs to the clinic: animal models of neuropathic pain. Br J Pharmacol 2014; 171: 2951-63.
  8. Fragaszy D, Simpson E. Understanding emotions in primates: in honor of Darwin’s 200th birthday. Am J Primatol 2011; 73: 503-6.
  9. Capogrosso M, Milekovic T, Borton D, et al. A brain-spine interface alleviating gait deficits after spinal cord injury in primates. Nature 2016; 539: 284-8.



ZARED O. is an 11th grader in high school. For the past two years he has served as an assistant in a research lab at a large hospital in the United States. His other interests include Boy Scouts, chess, tennis, ping pong, video games, cybersecurity, and Tae Kwon Do, in which he holds a 1st degree Black Belt.


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