 |
|
|
Chimpanzees in laboratories can exhibit behavioral abnormalities ranging from fear, depression, self-mutilation and inappropriate aggression. ©iStock.com |
|
Several recent studies point to the ability of chimpanzees to suffer psychological disturbances similar to those of humans when subjected to events often associated with life in a laboratory.
In addition, the studies have found that treatment of these ailments can be effective in increasing the wellbeing of chimpanzees.
Post-Traumatic Stress Disorder (PTSD) in Chimpanzees
The long-term psychological effects of experiencing or witnessing a traumatic event are well known in humans—post-traumatic stress disorder (PTSD) is common among humans. Now, in separate studies, researchers have concluded that chimpanzees used in invasive research experience similar long-term effects, reinforcing evidence that laboratory animals suffer both physically and mentally from their environment and experiences.
A paper, entitled "Building an Inner Sanctuary: Complex PTSD in Chimpanzees" [PDF] and published in the Journal of Trauma and Dissociation in April 2008, researchers analyzed the cases of two chimpanzees named Jeannie and Rachel who were used in research and retired to Fauna Foundation, a sanctuary in Canada. In that study, researchers found that the Jeannie's and Rachel's symptoms were representative of symptoms that human sufferers of PTSD experience.
The authors concluded that the conditions in laboratories (persistent stress, unpredictability and lack of control over environment) and the behaviors described and observed correlate with what has been defined as complex post-traumatic stress disorder in humans. These conditions continue today for those chimpanzees remaining in laboratories.
Most importantly, the study showed that chimpanzees experiencing PTSD symptoms can be successfully rehabilitated with therapies similar to those used to treat humans with the same disorder. The findings were presented in Edinburgh, Scotland at the 2008 International Primatological Society (IPS) Congress during a talk entitled Humane Considerations Regarding the Use of Chimpanzees in Biomedical Research and Testing [PDF]
Jeannie
Evaluation of the chimpanzees involved interviewing caretakers, observing the chimpanzees directly, looking through historical records, among other methods. According to the publication, Jeannie lived in three laboratories and was used in "intensive and invasive research" such as infection with HIV and hepatitis C virus, biopsies, and more than 200 "knockdowns." Personnel at the last laboratory she lived in described Jeannie as having a "nervous breakdown" and she was no longer used. Some behaviors she exhibited were spinning, self-injury, and unpredictable aggression, among others. During her time at Fauna Foundation she relied upon humans and other chimpanzees more and her symptoms decreased, but didn't stop completely.
|
 |
|
Chimpanzees deprived of socialization early in life have a difficult time with re-socialization and exhibit many abnormal behaviors. ©iStock.com |
Rachel
In Rachel's case, she was raised like a human and then sent to a laboratory at the age of three where she was housed alone for most of 15 years due to her aggression toward other chimpanzees as well as humans. When she arrived at Fauna, she was scarred from self-inflicted injury. Her social skills have improved and she has fewer violent episodes.
Two things that both chimpanzees have in common are that they were housed alone for at least a decade and experienced traumatic events early in life.
Other Behavioral Abnormalities in Chimpanzees
A 2006 review by Brüne et al. published in Neuroscience and Biobehavioral Reviews showed that captive chimpanzees can exhibit behavioral abnormalities ranging from fear, depression, self-mutilation and inappropriate aggression—symptoms similar to disorders in humans such as depression, anxiety and PTSD.
Some other recorded abnormalities seen in captive great apes include clapping, "raspberry" sounds, hair pulling, head banging, eye poking and feces smearing. Many of these behaviors have never been seen wild chimpanzees. The causes of these irregularities are thought to be early separation of infants from mothers, solitary housing and sensory deprivation—events often experienced at one time or another by chimpanzees in laboratory settings.
 |
|
|
Chimpanzees in laboratories endure early separation of infants from mothers, and some degree of solitary housing and sensory deprivation. ©iStock.com |
|
The review suggests potential treatments for these psychological abnormalities such as careful re-socialization, behavioral therapy and environmental enrichment of enclosures. However, despite these treatments, psychological disturbances may persist at which point pharmaceuticals used in humans may be considered as possible treatments to assist in recovery.
A study published in 2008 by Kalcher et al. focused on 18, wild-caught chimpanzees from laboratories who had previously had auditory and some visual contact with other chimpanzees, but no physical contact for a range of 16 to 27 years before they were re-socialized. The authors found that the earlier in life that the chimpanzees were socially deprived, the more likely they were to exhibit abnormal social behaviors into adulthood after re-socialization.
Finally, a study published in 2007 by Reimers et al. again focused on wild caught chimpanzees who had a history of social deprivation and who are now in sanctuary. This study again found that those that were deprived earlier in life had a more difficult time with re-socialization and exhibited more abnormal behaviors than those who had been deprived later in life. However, all of the chimpanzees experienced increased wellbeing from a rehabilitation and re-socialization program.
Conclusions
All of these studies, taken together, show that all-too-common experiences of chimpanzees in laboratories such as separation, isolation, lack of mental stimulation, and invasive procedures can lead to extremely negative psychological reactions in chimpanzees—much as they do in humans.
"These important studies show that chimpanzees clearly suffer in laboratory conditions," says Kathleen Conlee, director of program management for animal research issues at The HSUS.
"However, it is also clear that these chimpanzees can be rehabilitated, if given the proper environment and care. Therefore, it should be an urgent priority to get these highly sentient animals out of labs and into suitable sanctuaries where they can begin the rehabilitation that they need and deserve."
Citations
Brüne, M., Brüne-Cohrs, U., McGrew, W. and Preushoft, S. (2006). Psychopathology in great apes: Concepts, treatment options and possible homologies to human psychiatric disorders. Neuroscience and Biobehavioral Reviews, 30: 1246–1259.
Bradshaw, G., Capaldo, T., Lindner, L and Grow, G. (2008) Building an Inner Sanctuary: Complex PTSD in Chimpanzees. Journal of Trauma and Dissociation, 9(1): 9-34.
Kalcher, E., Franz, C., Crailsheim, K. and Preuschoft, S. (2008). Differential Onset of Infantile Deprivation Produces Distinctive Long-Term Effects in Adult Ex-Laboratory Chimpanzees (Pan troglodytes). Developmental Psychobiology, 50(8): 777-88.
Reimers, M., Schwarzenberger, F and Preuschoft, S. (2007) Rehabilitation of research chimpanzees: Stress and coping after long-term isolation. Hormones and Behavior, 51: 428–435
Updated March 20, 2009 
