Combination Therapy Reduces Self-injurious Behavior in a Chimpanzee (Pan Troglodytes Troglodytes): A Case Report

Abstract

Self-injurious behavior (SIB) remains a severe and intractable abnormal behavior for nonhuman primates in diverse settings and is a significant concern for veterinarians and behavioral scientists. To date, no single pharmacological, behavioral, social, or environmental intervention method has emerged as a reliable permanent cure for treating SIB in all, or even most, individuals. Implementation and evaluation of a combination therapeutic approach to treating SIB for nonhuman primates is rare. In May 2004, a 25-year-old male chimpanzee with severe SIB (M = 2.09 episodes/day, range = 1-4 episodes/day) underwent intensive behavioral intervention that utilized a combination of techniques. The combination therapy approach entailed the following: (a) pharmacological intervention with a gamma-aminobutyric acid (GABA) analogue to treat suspected HIV-related sensory neuropathic pain, (b) positive reinforcement training, and (c) environmental enrichment, as well as social and environmental modification. The severity of SIB warranted immediate implementation of intensive combination therapy rather than a systematic evaluation of the individual treatment options. The individually tailored, multifaceted combination therapy resulted in the virtual elimination of SIB in this chimpanzee over a 2-year period.

Stereotypical Behaviors in Chimpanzees Rescued from the African Bushmeat and Pet Trade

“…Almost all of the suggested forms of treatment are strategies implemented in various degrees by the Sweetwaters sanctuary. Additional treatments for self-injurious and stereotypical behaviors in chimpanzees include pharmacological interventions, and positive reinforcement training [11]. Given that only a small percentage of chimpanzees we initially surveyed the caregivers about met the criteria for PTSD or CPTSD, even if they did engage in at least one abnormal behavior, we agree with previous researchers that sanctuaries with enriched, social living arrangements and skilled, nurturing personnel are an effective form of treatment for most chimpanzees who experience disruptive maternal care and/or physical and psychological trauma [20].…”

“…In the wild, chimpanzees spend the first 5 years of their lives nearly inseparable from their mothers [6,7,8]. Similar to what happens in humans and other non-human primates, maternal deprivation and social isolation at an early age can result in chimpanzees developing a variety of abnormal behaviors that can persist in perpetuity [6,8,9,10,11,12,13,14,15,16,17,18]. Typically, behaviors are deemed “abnormal” if they are species atypical or occur only or more often in captive chimpanzees [6,18].…”

“…Since chimpanzees cannot give verbal reports of their symptoms, researchers have relied upon qualitative reports from their human caregivers. While some may dismiss a chimpanzees’ lack of the ability to verbalize the source of trauma or symptoms as a reason for why they cannot be diagnosed with psychopathologies, and suggest any attempt at doing so is anthropomorphism, others have argued that this is just as valid as a method as relying upon a human caregiver for reports of symptoms in a non-verbal human with a disorder, such as a small child [11,38]. Using this methodology, both PTSD- and CPTSD-like symptoms have been reported in chimpanzees who have experienced maternal deprivation, physical and psychological abuse, or who lived in deprived captive conditions [12,31].…”

How Abnormal Is the Behaviour of Captive, Zoo-Living Chimpanzees?

“…Many chimpanzees ( Pan troglodytes ) kept in laboratory housing settings show a variety of serious behavioural abnormalities, such as repetitive rocking, drinking of urine, or self-mutilation [4], [5], [6], [7], [8], [9], [10], [11], [12]. Previous work indicates that various abnormal behaviour patterns also occur among chimpanzees held in zoological collections [13], [14], [15], [16], but detailed, quantitative studies on the zoo population are few [17].…”

The beginning of the end for chimpanzee experiments?

“…It is increasingly acknowledged that such abnormal behaviors resemble symptoms associated with human psychiatric disorders, such as depression, anxiety disorders, eating disorders, and post-traumatic stress disorder, and that pharmacological treatment modalities similar to those applied to human patients may be appropriate, and indeed, morally compelled, for severely disturbed animal patients [100,103]. Long-term therapeutic combination with positive reinforcement training, environmental enrichment, and social and environmental modification may be necessary in severe cases [101]. …”