Itsy Bitsy Spider

Rosie, the tarantula

Rosie, the tarantula, is used in Dean Acheson's arachnophobia pilot project supported by CTRI.

Arachnophobia Study Funded by CTRI

September 26, 2013 - Her name is Rosie. She is a frightful sight, sending shivers of fear through most humans who see her. For some, that fear is debilitating.

Rosie is a "large hairy Chilean rose-haired tarantula," said Dean Acheson, an assistant professor at UC San Diego. Acheson is using Rosie in a Clinical and Translational Research Institute (CTRI) pilot project to study if the drug oxytocin can strengthen the outcome of exposure therapy for patients with arachnophobia – the fear of spiders. If the pilot project gleans promising results, Acheson plans to conduct larger studies with more complex conditions like obsessive-compulsive disorder or post-traumatic stress disorder.

"Exposure therapy uses fear extinction mechanisms," Acheson said. The patient, he explained, is gradually exposed to the object of their fear until they become comfortable with the object.

In the pilot project, oxytocin – called the "trust hormone" because it promotes social and emotional bonding – is combined with exposure therapy. "We have recently found that oxytocin, a mammalian peptide that modulates anxiety and cognition, may also facilitate fear extinction in humans," Acheson said.

Presently underway, the pilot project includes 24 patients with arachnophobia in a randomized, double-blind, placebo-controlled trial to assess how oxytocin may enhance exposure treatment. Four patients are presently participating in the study, with enrollment ongoing for the remaining 20 subjects. Acheson expects to conclude the study in March, 2014.

The study includes four sessions, beginning with a 45-minute initial assessment. During the treatment session one week later, the study patient receives oxytocin (or a placebo) through nasal spray, followed by 90 minutes of exposure therapy. The third and fourth sessions take place one week and four weeks after the treatment session. During each of those, the patient repeats the initial assessment with the addition of some questionnaires to assess patient experience of the treatment.

Acheson described the structured hierarchy of the treatment. "We start with a glossy print of a tarantula and wait until the patient's anxiety reduces. Next the patient holds the photo, until he or she is comfortable," he said. This is followed by the patient seeing the spider nine feet away in closed glass cage with a mesh top. Once comfortable, the patient moves to within five feet of the spider and eventually, if possible, to the spider.

Acheson said combining psychotherapy with pharmacotherapy "synergistically" is a newer way of looking at how to treat anxiety-related disorders. "With recent knowledge regarding the molecular processes and neurocircuitry involved fear extinction gained form basic neuroscience, the time seems ripe to pair these together," he said. "We hope that this paradigm can provide the next leap forward in increasing psychotherapy efficacy." The spider study is expected to demonstrate the effect of the drug on the mechanism of action underlying exposure-based psychotherapy. Essentially, does the drug make the therapy more durable? Do patients tested have a stronger memory of fear extinction? Most people are somewhat afraid of spiders, but for arachnophobia patients, that fear is much more debilitating. "Fear of spiders is universal. It is hard-wired," said Acheson, noting it likely had a purpose as a survival instinct in the evolutionary process. An image of a spider – flashed in a microsecond and imbedded within a series of benign images – will cause activation of the amygdala, a central component of the brain's fear network.

UC San Diego Assistant Professor Dean Acheson is conducting an arachnophobia pilot project supported by CTRI. Here he is with Rosie, the tarantula, and Assistant Mary Kamenski in the spider room at UC San Diego.

The patients Acheson is trying to help are those  whose fear of spiders noticeably restricts their  activities and quality of life. For instance, they won't go on camping trips because there are spiders in the woods or to a utility closet because it's in a basement or to their child's outdoor sports activities.

The CTRI pilot project program, which funds projects for clinical researchers early in their careers, supports Acheson in his goal, which is ultimately to help patients improve their lives. "When a patient comes to my office and is not functioning because of an obsession or a phobia, goes through exposure therapy, and, a few months later, is living a fuller life, it gives meaning to my research," Acheson said. "It is so rewarding. You understand where your research is going and why. The spider study helps to take that research to the next level, moving from basic science to clinical application."

"The pilot project program at CTRI was created to encourage young investigators to conduct clinical trials and other translational research early in their careers. We look forward to seeing the findings from Dr. Acheson's clinical trial," said Murray Stein, MD, MPH, Pilot Projects Director at the UC San Diego CTRI.

The CTRI pilot project award for the spider study is $25,000 for one year, covering the expense of the spider and supplies, pharmacy start-up costs, the drug, compensation for the subjects, and the salary for Acheson's assistant, Mary Kamenski. The exposure therapy takes place in the spider testing room at UC San Diego Medical Center in Hillcrest.

And Rosie? Well, she has the life, according to Acheson. She hangs out in a comfortable home with a live cricket that, when she is hungry, will be dinner. Click here for more information about the CTRI pilot project. If you are interested in enrolling in the spider study, contact Mary Kamenski at (619) 543-3582.

Written by Patti Wieser