The Impact of Sex Hormones on One-session Treatment for Spider Phobia in Women
Condition: Phobia, Specific
MeSH terms: Phobic Disorders
Study type: Interventional

Summary: 
      The purpose of this study is to determine whether levels of sex hormones (including estrogen
      and progesterone) influence women's response to treatment for Specific Phobia of spiders. It
      is hypothesised that women will show less relapse of symptoms of spider phobia if they
      receive treatment during a period of high levels of sex hormones.
    

Detailed description: 
      Detailed description of the Behavioural Avoidance Test (BAT):

      Participants will be asked to stand in front of a closed door. They will be asked by the
      experimenter to approach the spider as closely as possibly, but they are reminded they can
      stop at anytime. Participants will then enter a room in which a table will be located
      approximately 3 meters in front of them. On top of the table will be a glass terrarium
      containing a fast moving spider (Huntsman - Holconis). These spiders were chosen because they
      are all low risk (non toxic) and non-aggressive to humans. In addition, these spiders are
      also commonly found in homes or gardens, thus increasing the ecological validity of our
      study. Participants will be asked to approach the spider in a stepwise manner (i.e., in 10
      steps). Performance will be scored on a 10-point scale that corresponds with the steps taken
      during the test; the steps are 0 = refuses to enter room, 1 = stops 3m from terrarium, 2 =
      stops 2m, 3 = stops 1m, 4 = stops close to terrarium, 5 = touches terrarium, 6 = removes lid,
      7 = puts hand in terrarium, 8 = touches inside walls and floor of terrarium, 9 = guides
      spider over hand which is resting on the floor of the terrarium. For steps 7 to 9 the
      experimenter will relocate the spider to a larger enclosure with a zippered opening that can
      be arranged so the spider cannot escape the enclosure and the participant will be provided
      with a long sleeved shirt and a gardening glove. Once the participant has entered the room,
      the experimenter does not persuade the participant to continue.

      Detailed Description of One-Session-Treatment (OST):

      There will be three sessions. Session 1 involves the preparation stage, a pre-treatment
      interview, pre-treatment measures, and OST. During the pre-treatment interview a clinical
      psychologist will collect information about the participants fear of spiders and provide a
      rationale for treatment. The participant will then complete pre-treatment measures, including
      the BAT (to assess pre-treatment levels of avoidance; see detailed protocol above), as well
      as self-report questionnaires. After completing the pre-treatment measures, participants will
      then begin OST. This treatment will strictly follow Öst's manual for specific phobias. It
      will take a maximum of three hours and has been shown to be highly effective in treating
      specific phobia, including spider phobia. OST involves the use of a maximum of 4 spiders of
      varying sizes, from 0.5cm to 5cm, housed in glass terrariums. Two spider species will be
      used: St Andrew's Cross (Argiope) and Huntsman (Holconia immanis). These spiders were chosen
      because they are all low risk (non toxic) and non-aggressive to humans. In addition, these
      spiders are also commonly found in homes or gardens, thus increasing the ecological validity
      of our treatment. There are a total of five steps and at the start of each step, the
      experimenter will provide instructions and then model the behaviour for the participant. Each
      step will be repeated until the participant experiences a reduction of at least 50% in their
      anxiety, as assessed by Subjective Units of Distress ratings (SUDS; 0-100), or rate the
      conviction in their belief that a catastrophe will occur as 0 (0-100). Steps 1-4 will be
      completed with the St Andrew's Cross spiders. Step 1 involves teaching the participant how to
      catch the smallest spider with a glass and postcard (i.e., placing glass upside down over the
      spider in the terrarium and to slide the postcard underneath). Step 2 involves touching the
      spider from behind with the dominant index finger. Step 3 involves letting the spider walk on
      the participant's hands. Step 4 involves allowing the spider to walk on the participant's
      legs and body. Steps 1-4 are then repeated with larger St Andrew's cross spiders. After
      completing this, the participant will be encouraged to have the two largest St Andrew's cross
      spiders walk on their hands simultaneously. Step 5 is provided in the treatment as an extra
      step and will be completed only if there is time remaining and if the participant gives
      consent. Step 5 involves encouraging the participant to complete the final step of the BAT
      using the Huntsman spider (i.e., guiding the spider over their gloved hand). The experiment
      ends when all steps are completed, or if the maximum 3 hour time limit has been reached, or
      if the participant indicates that they do not want to continue. After treatment, participants
      will be checked to ensure they are not feeling any distress and will be accompanied by the
      experimenter to Healthscope Pathology to provide a blood sample to verify hormone levels.

      Session 2, a follow-up session, will occur one-week later, as per Öst's treatment manual.
      During this session, post-treatment measures will be taken, including structured clinical
      interview assessment, self-report questionnaires and BAT.

      Session 3 will occur 3 months later and will be a long-term follow-up session. Participants
      will undergo the same measures as in session 2. Participants will be fully debriefed
      regarding the aims and implications of the experiment. During this process, participants will
      be asked if they have any questions or concerns, and will be checked to ensure they are not
      feeling any distress.
    

Intervention name(s): One-Session-Treatment
Intervention type(s): Behavioral
Intervention description(s): There are a total of five steps, each to be repeated until the participant experiences a reduction of at least 50% in their anxiety. Step 1 is catching a spider with a glass and postcard. Step 2 is touching a spider from behind with the dominant index finger. Step 3 is letting a spider walk on the participant's hands. Step 4 is allowing a spider to walk on the participant's legs and body. Steps 1-4 are repeated with larger spiders, and then the two biggest spiders will walk on the participants' hands simultaneously. Step 5 is using a chopstick to guide a huntsman spider over their gloved hand. Treatment ends when all steps are completed, or if the maximum 3 hour time limit has been reached, or if the participant indicates that they do not want to continue.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment