Table 3: Studies investigating EX in the therapy of illicit drug abuse/dependence.

First author, yearSample characteristicsStudy design, standard therapyExercise intervention (EX)Control condition(s)Outcome variables and findings
Exercise > control condition

Collingwood et al. (1991) [37]- 𝑁 = 7 4 teenagers (mean 16.8 y)
- at-risk of drug abuse or abusing drugs or drug-dependent (m, f)
- Ethnicity not reported
- 𝑁 = 5 4
secondary school at-risk classes drug prevention program
- 𝑁 = 1 1 community-based substance abuse counseling agency program duration
- 𝑁 = 6 weeks 𝑁 = 9 inpatient chemical dependency unit treatment
- Duration: 8 weeks
- Duration: 9 Weeks
- 1-2 times/week supervised group EX, 2 individual weekly training sessions
- 60–90 min, stretching, strength development, individual aerobic EX
- None
- statistical comparison between subjects with ( 𝑁 = 3 8 ) versus without ( 𝑁 = 3 6 ) significantly increased fitness (“improvers” versus “non-improvers”)
- “Improvers”: significantly fewer multiple drug users and alcohol uses per week, and higher abstinence rate (but no differences concerning the use of individual substances)
- Significantly higher flexibility and strength, and lower body fat
Stronger decrease of depression and anxiety, more positive self-concept
- No experimental design
- Post hoc classification possibly confounded with other variables (EX adherence and abstinence may depend on the same external factors; causality is not given)
- Heterogeneity of diagnoses and institutions
- Significant differences between groups concerning initial fitness levels, self-concept, abstinence rates, depression, and anxiety
- Drug use only assessed by self-report

Burling et al. (1992) [38]- 𝑁 = 2 1 8 veterans with drug and/or alcohol abuse or dependence (m)
- Mixed sample (50% Black, 41% White, 9% other)
- Inpatient rehabilitation program for homeless substance-dependent veterans
- Group-based CBT skills training
- Duration ≥ 30 days
- Duration ≥ 30 days (optional continuation as outpatient)
- Softball team ( 𝑁 = 3 4 ) : 2 trainings, one game (men’s city league), one team meeting/week
- Two control cohorts:
- A: 𝑁 = 1 0 2 , patients treated at the same time who chose not to participate in EX
- B: 𝑁 = 8 2 , patients treated 1 year prior to EX cohort
- Significantly higher abstinence rate in softball cohort at 3-month followup
- Trend for higher employment and dwelling
- Significantly higher treatment duration and completion
- Unequal group sizes (32 : 102 : 82)
- Self-selection of participants, no randomization
- Lack of pure EX intervention includes social interaction, team-building, and time structuring
- Lack of equal contact time control group controlling for these factors
- Cultural specificity of softball (lack of generalizability)

Palmer et al. (1995) [39]- 𝑁 = 4 5 patients with “problems with alcohol, cocaine or other drugs” (m, f)
- (diagnoses not specified)
- Mixed sample (60% Black, 40% White)
- Inpatient rehabilitation program
- Duration: 28–45 days
- Random assignment to one of three EX conditions
- Duration: 4 weeks
- 3 times/week, 30–40 min supervised EX
- A: step-aerobic program at 60% max HR (aerobic training)
- B: body-building program (anaerobic strength training)
- C: circuit training (mixed aerobic and anaerobic training)
None- No drug-related outcomes reported
- No fitness gains in either group after 4 weeks
- Significantly reduced depression scores in group B (bodybuilding), no changes in groups A and C
- No changes in blood pressure or resting pulse
- Small N
- Heterogeneity and lack of clarity concerning the diagnoses
- Initial differences between groups concerning depression scores significant reductions in group B possibly explained by higher initial scores
- Training in group B in teams of 2-3, in A and C alone social confounds
- EX duration too short to improve fitness
- Lack of intention-to treat analysis to correct for high number of dropouts
- No follow-up data reported

Williams (2000) [40]- 𝑁 = 2 0 “asymptomatic offenders” (m, f) consuming metamphetamine, alcohol, cannabis, or other drugs
- (diagnoses not specified)
- Mixed sample (70% Caucasian, 20% Hispanic, 5% Afro-American, 5% native American)
- Outpatient community-based treatment program with 2 weekly sessions for relapse prevention
- Duration: 12 weeks
- Duration: 12 weeks
- Daily journals recording PA and optional 2 times/week of supervised muscle strengthening training
- None
- post hoc comparison between program “completers” and “non-completers”
- No drug-related outcomes reported
- “Completers” more involved into EX behavior even before the treatment
- Subjects agreed that EX was effective in preventing them from relapse
- Very small 𝑁 (9 dropouts), no meaningful statistic
- No group assignment, no control group
- Post hoc classification possibly confounded with other variables (EX adherence and abstinence may depend on the same external factors; causality is not given)
- Self-selection of participants

Li et al. (2002) [41]- 𝑁 = 8 6 heroin-dependent patients (m)
- Ethnicity not reported
- Mandatory inpatient treatment
- Duration: 1–3 months
- Duration: 10 days
- 4-5 times/day
- 25–30 min Pan Gu Qigong
- A: 10 days of medication with lofexidine HCl
- B: detoxification without special treatment except for PRN medication against severe withdrawal symptoms
- Fewer withdrawal symptoms and earlier negative morphine test in Qigong group
- Fewer symptoms of anxiety in Qigong group compared to control groups A and B
- Ethical problems (mandatory treatment)
- Lack of specific EX intervention (multifaceted intervention)
- Cultural specificity of Pan Gu Qigong (lack of generalizability)
- Initial group differences on day 1 concerning withdrawal symptoms faster reductions possibly explained by lower initial scores
- No follow-up data for postacute phase reported

Roessler (2010) [42]- Pilot study 𝑁 = 3 8 patients dependent of cannabis, opiate, medication, heroine, cocaine, and/or amphetamine (m, f)
- Ethnicity not reported
- Day clinic for substance dependent patients,
- (type of treatment not reported)
- Duration: 2 and 6 months, respectively
- Duration: 2 and 6 months, respectively
- 3 times/week 2h of endurance training, strengthening EX, and team sports (badminton, volleyball)
None- Improvements in subjective control, craving, role of the substance
- Significantly improved fitness at end of treatment
- subjective reports: increased fitness reduces withdrawal symptoms and improves body perception, vigor, sleep quality, and self-confidence
- Very small N, very high dropout rates ( 𝑁 = 1 7 for pre-post comparison)
- Sample selected by clinic staff based on physical condition, compliance, and so forth.
- Lack of control group changes cannot be attributed to EX
- No validation of self-reported substance use

Brown et al. (2010) [43]- Pilot study 𝑁 = 1 6 untrained patients dependent of alcohol, cannabis, cocaine, opiates, and/or sedatives (m, f)
- Mixed sample (81% Caucasian, 13% Afro-American, 6% Hispanic)
- Different concurrent treatments for substance use (inpatient, outpatient, day-clinic, individual sessions with psychiatrists)
- Duration: not standardized
- Duration: 12 weeks
- 1 supervised and 2-3 individual training sessions per week, progressively 20–40 min of moderate aerobic training (55–69% max HR)
- 1 brief weekly CBT intervention to increase motivation for PA
- incentive component for EX adherence
None- At end of treatment, 66% of patients abstinent, with significantly lower relapse rates in patients who had attended at least 75% of EX sessions
- Significantly increased fitness after 12 weeks
- Very small 𝑁 , high dropout rate
- Lack of control group changes cannot be attributed to EX alone
- EX adherence and abstinence may depend on the same external factors (causality not given)

Buchowski et al. (2011) [44]- Pilot study 𝑁 = 1 2 untrained cannabis-dependent patients not seeking treatment for their cannabis dependence
- Ethnicity not reported
None- Duration: 2 weeks
- 5 times/week supervised training session (total of 10)
- 30 min moderate treadmill walking/ running
None- Cannabis consumption significantly reduced compared to baseline during intervention and at 2-week followup
- Significantly reduced craving after each training session
- Very small N
- Lack of control group, no substance-related intervention
- EX duration too short to improve fitness
- Only self-report of cannabis consumption
- Motivation of patients unclear: ostensibly no desire for change concerning cannabis consumption, but very high adherence rates

AA: alcoholics anonymous, ACSM: American College of Sports Medicine, CBT: cognitive-behavioral therapy, EX: exercise, f: female, h: hour(s), HR: heart rate, HR-R: heart rate reserve, m: male, max HR: maximum heart rate, min: minutes, N: sample size, PA: physical activity.