Materials and Methods.
Design. The study used a double-blind, within-participant
design in which healthy adults received MDMA (100mg), MA (20mg) and
placebo (PLC) on three separate sessions. At the expected time of peak
drug effect participants engaged in an oddball task during which we
recorded EEG responses to positive, negative, and neutral faces. ERP
components related to different aspects of emotional and cognitive
processing were recorded. Participants also completed self-report
measures of the drugs’ effects.
Participants. Healthy men and women (N=25) aged 18-35 were
recruited from the university and surrounding neighborhoods. Eligibility
was determined first by online screening and then by clinical interview
and physical examination. Inclusion criteria consisted of a minimum high
school education, fluency in English, BMI 18-26, and good health.
Exclusion criteria included use of prescription medications, history of
cardiac disease or high blood pressure and previous negative experience
with MDMA or hallucinogenic substances. Participants had to report
between 4 and 40 previous experiences of MDMA to qualify for the study.
Women who were not on oral contraceptives were tested only during the
follicular phase (1-12 days from menstruation; White, Justice et al.
2002).
Procedure. Participants first attended an orientation to
understand the procedures, provide informed consent and practice the
tasks from the experimental sessions. They were instructed to abstain
from drugs and alcohol for 24 hours before their sessions. They were
told they would receive a sedative (e.g., Valium) ,stimulant (e.g., MDMA or amphetamine), or placebo drug in
each session. The study was approved by the local institutional review
board.
The three, four-hour drug sessions were conducted from 9am-1pm,
separated by at least 4 days (M=7.5 days). Upon arrival at the
laboratory, participants completed a breathalyzer and urine sample to
test for recent drug use (CLIA waived Instant Drug Test Cup, San Diego,
CA; amphetamine, cocaine, oxycodone, THC, PCP, MDMA, opiates,
benzodiazepines, barbiturates, methadone, methamphetamine,
buprenorphine), alcohol use (Alcosensor III, Intoximeters, St. Louis,
MO) and pregnancy (in females; Aimstrip, Craig Medical, Vista, CA). They
completed pre-capsule questionnaires and cardiovascular measures,
measures that were repeated 60, 90, 180 and 240 minutes after the
capsule. They ingested capsules containing dextrose (placebo), MA (20mg)
or MDMA (100mg) under double blind conditions. Thirty minutes after
taking the capsule participants’ EEG electrodes were placed, and
recording began about 60 minutes after the capsule. Resting state EEG
was determined first, and this was followed by three tasks completed in
randomized order. Here we report data on an emotional oddball task
assessing responses to happy, angry, and neutral faces (Raz et al.,
2014). The EEG measures were obtained from 60 to 150 min post-capsule.
After the EEG electrodes were removed, participants rated the arousal
and valence of the faces they viewed during the EEG task. Participants
left the laboratory after the final measure, 240 min post capsule.
Drugs: MDMA in powdered form (100 mg; Organix Inc, MA) was
placed in opaque size 00 capsules with lactose filler. MA tablets (5 mg,
total dose 20 mg; Desoxyn, Lundbeck) were placed in an opaque size 00
capsule with dextrose filler, and placebo capsules contained only
dextrose.