Conditions: Posttraumatic Stress Disorder
Keywords: PTSD
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 54
Healthy volunteers: no

Brief summary:
The purpose of the proposed study is to determine if pairing reactivation of a traumatic memory with a single administration of Rapamycin (e.g., Sirolimus) in men with combat-related Posttraumatic Stress Disorder leads to a reduction of the emotional strength of that particular traumatic memory.

The following hypotheses will be tested:

1. Traumatic memory reactivation paired with a single dose of Rapamycin will decrease objective measures of stress and self-report of stress during replay of the traumatic memory, relative to, subjects receiving placebo.
2. Pairing administration of Rapamycin with traumatic memory reactivation will decrease symptoms of Posttraumatic Stress Disorder one month and three months later, relative to patients receiving placebo.

Detailed description:
Post-traumatic stress disorder (PTSD) is characterized by intrusive memories in the form of unwanted images, nightmares, and flashbacks as the result of being exposed to a traumatic event . Current research efforts have begun to explore the underlying neurochemical changes associated with PTSD. Recently, these efforts have focused on the prevention of PTSD in persons exposed to trauma. For example, preliminary evidence suggests that interference with consolidation of trauma-related memories using the beta-antagonist, propranolol, may prevent PTSD in humans with recent traumas. However, given that as much as 90% of the US population is exposed to at least one traumatic event during their lifetimes, the utility of this treatment is limited by the logistical problems of treating everyone at risk. To date, there have been very few systematic studies on humans that focus on changing the underlying traumatic memory once PTSD has been established.

The trauma experience is initially stored in short-term memory, then consolidated into long-term memory. However, the long-term stability conferred by the consolidation process undergoes a period of labiality as follows. Each time a consolidated memory is activated, the memory trace becomes newly labile and must be consolidated again to remain in long-term memory5. This process is called reconsolidation. Reconsolidation therefore offers a biologic window during which long-term memories can be disrupted. Preclinical studies have begun to unravel the biological changes that underlie these processes. Both pharmacological agents, including glucocorticoids, and protein synthesis inhibitors can interfere with memory consolidation and reconsolidation. In preclinical studies, the global protein synthesis inhibitor anisomycin can block reconsolidation, leading to a reduction in strength of traumatic memories. Unfortunately, the toxicity of anisomycin is prohibitive for therapeutic use. Thus, rather than using a global protein synthesis inhibitor, a more effective and selective means of reducing consolidation of an established traumatic memory is to target only a subset of protein translation important for synaptic plasticity. The protein kinase mTOR (mammalian target of rapamycin) is just such a regulator of a subset of protein synthesis critical for synaptic plasticity.

Arms:
arm 1: 15 mg Placebo will be administered once, in pill form. arm 2: 15 mg of Rapamycin will be administered once, in pill form.

Interventions: intervention 1: Rapamycin intervention 2: Placebo
Intervention descriptions: intervention 1: Sirolimus is an FDA approved immunosuppressant drug used to prevent rejection in organ transplantation, and is especially useful in kidney transplants. It is non-toxic to kidneys, unlike other immunosuppressants. In this study, the medication will be administered once to see if it interferes with emotional memory reconsolidation. This is based on the fact that it inhibits the mammalian target of Rapamycin (mTOR) through directly binding the mTOR Complex1 (mTORC1). mTOR is a serine/threonine protein kinase that regulates cell growth, cell proliferation, cell motility, cell survival, protein synthesis and transcription.

a single dosage of 15mg will be administered during this study. intervention 2: Inactive

Protocol document: