American researchers compared biologically targeted imagery (BTI) and critical thinking asthma management (CTAM) outcomes. Participants were randomised to BTI (group 1, G1) or CTAM (group 2, G2) in a 2 × 2 × 4 design [BTI/CTAM × pretest/post-test × weeks (3-week averaged intervals of symptoms and peak flows)]. Interventions were asthma education plus treatment (BTI or CTAM for two 2-h sessions per week for 6 weeks). For BTI, data collection (symptoms and lung function) occurred pre-intervention (3-week baseline), during the intervention (6 weeks) and post-intervention (6 weeks). For CTAM, data collection occurred at waitlist control (WLC) (12 weeks extended baseline), pre-intervention (3 weeks), during the intervention (6 weeks) and post-intervention (6 weeks). Dependent variables included asthma symptoms (wheezing, coughing, sleep, activity, attacks and peak flow) and self-report assessments of Profiles of Mood States (POMS-BI) (anxiety, hostility, depression, uncertainty, fatigue and confusion); Knowledge, Attitude, and Self-Efficacy Asthma Questionnaire; Health Attribution Test for locus of control (LoC); and the Revised Asthma Problem Behavior Checklist. Analyses of covariance with repeated measures contrasted BTI pre- to post-tests, time periods and WLC; CTAM pre- to post-tests, time periods and extended baseline WLC; and BTI to CTAM outcomes. WLC improved all POMS-BI scores except anxiety, increased internal LoC and reduced problematic behaviours. Compared to WLC, BTI reduced wheezing, anxiety and chance LoC, and increased asthma knowledge, attitude and self-efficacy. Compared to CTAM, BTI reduced wheezing and chance LoC, increased internal LoC and improved six POMS-BI scores. Compared to extended baseline WLC, CTAM increased asthma knowledge, attitude, self-efficacy, internal LoC and peak flow.