Exercise to Improve Outcomes of Treatment for Methamphetamine Users

Participants were recruited to the study using various methods, including word of mouth and IRB-approved flyers posted throughout the treatment facility. Onsite study staff screened MA-dependent clients in a private study office and reviewed the informed consent protocol. After completion of informed consent procedures, participants entered a1-2week screening phase to determine eligibility, consisting of medical history, physical exam, laboratory studies, and ECG. Eligible clients were taken through study baseline assessments to inform randomization to study conditions, either an exercise intervention or health education control, using a computerized urn randomization program that stratified clients to conditions based on gender (male/female) and severity of baseline MA use (higher vs. lower severity). The cut-off point for determining lower severity MA use versus higher severity use was identified using data from previous clinical outcome studies that show the median number of days of MA use ranges from16 to 20 days at treatment entry. Hence, we defined "lower severity" as using MA for 18 or fewer days in the previous month, and "higher severity" as using for 19 or more days in the past month. The study's data management center (DMC) maintained the urn randomization program and the records that linked participant identification numbers to study condition. Study interventions were conducted onsite while participants were enrolled in usual care at the residential treatment facility; cases of early discharge from the facility resulted in premature termination from the study.

Participants randomized to the exercise condition received a structured exercise program 3 times a week for 8 weeks. Exercise sessions consisted of a 5-min warm-up, 30 min of aerobic activity on a treadmill, followed by 15 min of weight training and a 5-min cool-down/stretching period. Each session was monitored by a staff exercise physiologist who guided one to two participants at a time. Using heart rate monitors, the exercise physiologist worked closely with each individual participant on exercise days to increase treadmill speed/slope to maintain a heart rate between 60% and 85% of maximum for 30 minutes. Once a participant was able to complete two sets of 15 repetitions of any given exercise, weight was incrementally increased.

A data collection protocol occurred at baseline, and also weekly during the 8-week study period, at termination of the study period, and at 1-, 3-, and 6-months post treatment from the residential program (approximately 7-10 days following completion of the intervention period). Participants were compensated $40 per data collection session.

Inclusion criteria

• Be seeking treatment for their MA dependence;
• Be 18 years of age or older, and 45 or younger for males, 55 or younger for females;
• Meet DSM-IV-TR criteria for MA dependence;
• Have vital signs that are within clinically acceptable normal range, e.g., resting pulse between 50 and 90 /min, blood pressures between 85-150mm Hg systolic and 45-90mm Hg diastolic;
• Have a medical history and physical examination that, in the judgment of the study physician or Principal Investigator, show no clinically significant contraindications for study participation;
• For females, provide negative pregnancy urine tests before randomization (and for the sub-sample, another negative test before the final PET scan at the conclusion of the intervention).

Exclusion criteria

• Clinically significant heart disease or hypertension; unstable pulmonary or cardiovascular disease that would interfere with participation in exercise regimen
• Neurological or psychiatric disorders as assessed by MINI or clinical interview, such as psychosis, bipolar illness, Tourette's syndrome, major depression, organic brain disease, dementia, or any other neuro-psychiatric disorder that would require ongoing treatment or that would make study compliance difficult;
• Musculoskeletal disease that would prevent participation in exercise regimen
• Baseline ECG showing evidence of cardiac ischemia, arrhythmia, or other clinically significant abnormalities
• Untreated or unstable medical illness including: neuroendocrine, autoimmune, renal, hepatic, or active infectious disease (other than HIV) that requires immediate medical attention;
• Clinically significant abnormalities in hematology and chemistry laboratory tests that may make participation hazardous;
• Have HIV and unable to obtain a clearance for participation from his/her AIDS medical care provider;
• Pregnant;
• Any other illness, condition, or use of medications that, in the opinion of the PI and/or the study physician, would preclude safe participation or completion of the study.