Dronabinol in Trichotillomania and Other Body Focused Repetitive Behaviors
Condition: Trichotillomania; Skin-Picking
MeSH terms: Trichotillomania
Study type: Interventional
Phase: Phase 2/Phase 3

Summary: 
      The goal of the proposed study is to evaluate the efficacy and safety of dronabinol in
      trichotillomania and other body-focused repetitive behaviors such as skin-picking disorder.
      50 subjects with DSM-5 trichotillomania or skin-picking disorder will receive 10 weeks of
      double-blind dronabinol or placebo. The hypothesis to be tested is that dronabinol will be
      effective and well tolerated in patients with trichotillomania and/or skin-picking disorder
      compared to placebo. The proposed study will provide needed data on the treatment of
      disabling disorders that currently lacks a clearly effective treatment.
    

Detailed description: 
      Pathological hair-pulling, trichotillomania, has been defined as repetitive, intentionally
      performed pulling that causes noticeable hair loss and results in clinically significant
      distress or functional impairment. Although discussed in the medical literature for over one
      hundred years, and affecting all strata of society, there have been no epidemiological
      studies detailing how common trichotillomania is and there are no clear treatment approaches
      for everyone with trichotillomania. Behavioral therapy is generally regarded as the
      first-line treatment but trained therapists are difficult to find. In addition, there is no
      medication currently approved by the Food and Drug Administration for trichotillomania.
      Trichotillomania is related clinically to other BFRBs, specifically skin picking disorder. In
      fact, it appears that trichotillomania and skin picking disorder may in fact share a common
      neurobiology. Other BFRBs such as skin ppicking disorder also lack any agreed upon medication
      intervention, but evidence suggests that both skin picking disorder and trichotillomania may
      respond to the same interventions.

      The Trichotillomania Impact Project survey showed that only 15% of adults in the community
      with trichotillomania reported experiencing significant improvement with treatment of their
      symptoms. This may be because of the ongoing difficulty of finding a therapist experienced in
      trichotillomania treatments. More than 55% of persons in this survey believed that their
      clinician did not have sufficient knowledge of the disorder, and less than one-third were
      receiving evidence-based treatments for trichotillomania.

      A recent meta-analytic study of randomized treatment trials in adults demonstrated that
      behavioral treatments, mainly habit reversal therapy, have the greatest efficacy in treatment
      of trichotillomania. Selective serotonin reuptake inhibitors (SSRIs) are the most widely used
      treatment for adults with trichotillomania, despite evidence that their efficacy is no
      greater than placebo.

      Instead of using SSRIs, the investigators conducted an open-label study of dronabinol a
      synthetic form of tetrahydrocannabinol (THC) approved by the FDA as an appetite stimulant for
      people with AIDS and antiemetic for people receiving chemotherapy, in 14 women with
      trichotillomania and found that 9 (64.3%) responded to treatment and that the mean effective
      dose was 11.6 ± 4.1 mg/day.

      A recent study using diffusion tensor imaging demonstrated that both trichotillomania and
      skin-picking subjects exhibited significantly reduced fractional anisotropy in anterior
      cingulate, presupplementary motor area, and temporal cortices. These data suggest that the
      disorganization of white matter tracts in motor habit generation and suppression may underlie
      the pathophysiology of these disorders. Neurochemically, motor habits may rely partially on
      the endocannabinoid system. CB1 receptors are highly expressed in the basal ganglia nuclei,
      the hippocampus, cerebellum, and neocortex and are implicated in attenuating glutamatergic
      exocitotoxic damage by suppressing the neuronal release of glutamate via inhibition of
      calcium channels. The activation of CB1 receptors reduces glutamate release in the dorsal and
      ventral striatum [possibly through an interaction with brain-derived neurotrophic factor],
      thereby modulating neurotransmission in the basal ganglia and mesolimbic reward system .
      Stress-induced anxious behavior has been associated with the loss of CB1 receptor function in
      the striatum.

      Glutamatergic dysfunction has been implicated in the pathophysiology of trichotillomania.
      Pharmacotherapies, such as dronabinol, that target excessive glutamatergic drive through its
      effects on CB! Receptors may, therefore, be expected to correct the underlying
      pathophysiology and symptoms of trichotillomania.

      In the USA, dronabinol is FDA-approved for the treatment of anorexia associated with weight
      loss in patients with AIDS and nausea and vomiting associated with cancer chemotherapy. In
      our previous study examining dronabinol for trichotillomania, doses between 5 and 15mg/day
      were well tolerated and beneficial. This lack of significant side effects is consistent with
      other studies of dronabinol where it has been associated primarily with central nervous
      system-related adverse events (for example, confusion, dizziness, euphoria, and somnolence),
      but these adverse events are generally mild to moderate in severity and generally reversible
      upon dose modification.

      Given the serious personal consequences associated with trichotillomania, and the likelihood
      of success of dronabinol in treating the disorder, the aim of the present study was to
      examine the efficacy and safety of dronabinol vs placebo in adults with trichotillomania
      using a double-blind, placebo-controlled design.

      The investigators hypothesize that dronabinol will be more effective than placebo in reducing
      the frequency of hair pulling and in improving overall psychosocial functioning after 10
      weeks of treatment when compared to baseline.
    

Intervention name(s): Dronabinol; Placebo
Intervention type(s): Drug; Drug
Intervention description(s): Dronabinol for 10 weeks (5mg per day first 2 weeks, 10mg per day second two weeks, 15mg per day last six weeks); Placebo for 10 weeks
Other intervention name(s): Marinol
Intervention MeSH terms: Dronabinol
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Treatment