Assessment of Cannabis Craving in Schizophrenia Using Virtual Reality

Objective: The use of cannabis is prevalent in people with schizophrenia, and has been linked both to onset of illness and worsening of symptoms. Craving in persons with schizophrenia who use cannabis has not been widely studied. The occurrence of craving may lead to relapse in substance use disorders. Therefore, craving paradigms in people with schizophrenia need to be optimized in order to test new treatments on craving measures in this population. Thus, the purpose of this study is to determine the feasibility and effects of virtual reality cues on craving intensity for cannabis in patients with schizophrenia

Study population: We will enroll 25 persons with a DSM IV diagnosis of schizophrenia who have a lifetime history of at least 50 lifetime uses of cannabis and cannabis use an average of at least once per month (or, if inpatients, average use of once per month prior to hospitalization) with a goal of 16 completers.

Design: This study uses a comparison-controlled, within-subject design. All subjects will undergo a baseline assessment and acclimation period and then participate in an experimental condition in which four cues will be presented in separate rooms in the VR program. These include two cannabis cues and two neutral cues in four different rooms. A follow up session for craving and symptom assessments will occur one week after the experimental session.

Outcome Measures:

At the end of each of the four cues, the Cannabis Craving Scale (CCVAS), Cannabis Attention scale (CAS), the Marijuana Craving Questionnaire-Short Form (MCQ-SF), and a visual analog cigarette craving item will be administered to measure craving during the virtual reality session. The CCVAS and CAS will be projected into the VR environment and participants will respond via hand controller. The MCQ-SF will also be administered, as well as the Mood form , to assess mood, at baseline as well as at the end of each of the 4 cues. Before and after the experimental session participants will also be rated on the Brief Psychiatric Rating Scale (BPRS), Schedule for the Assessment of Negative Symptoms (SANS), side effects, and the State-Trait Anxiety Inventory (STAI). The Immersion Questionnaire and Imagery Realism Presence Questionnaire (PQ) will be given at the conclusion of the experimental session. Before and after the session, as well as during the experiment participants will be monitored for physiological reactivity (heart rate, blood pressure, and skin conductance response) to cues of cannabis use as well as neutral cues measured.