Acceptance and Commitment Therapy (ACT) in Hospitals and Primary Care: A Systematic Review Of Clinical Trials
acceptance and commitment therapy; hospital; primary care; efficacy; systematic review.
This systematic literature review aimed to investigate empirical evidence regarding the use of
acceptance and commitment therapy (ACT) in non-psychiatric hospital and Primary Health Care (PHC)
settings. Specific objectives included identifying the research context, target populations, research designs,
and control groups, as well as characteristics of interventions, dependent variables, measurement
instruments, and outcomes achieved. The method adhered to PRISMA guidelines, and the study was
registered with the PROSPERO system. Articles published from January 1, 2000, to May 1, 2022, were
searched in ProQuest, PubMed, Virtual Health Library (VHL), Academic Search Premier, and PsycNET.
Inclusion criteria comprised clinical trials with clear objectives, methods, and results; target populations
undergoing ACT interventions in non-psychiatric hospitals and PHC; ACT as the primary psychological
intervention; reported dependent variables; articles in Portuguese, English, or Spanish; and peer-reviewed
journals with full-text availability. Search terms in English were (“acceptance and commitment therapy”)
AND (“hospital*” OR “primary care”), their Portuguese and Spanish versions, with syntax variations
depending on database. The author and two other psychologists independently reviewed titles and
abstracts for study exclusion, resolving disagreements through consensus. Of the 29 reviewed articles, 11
(37.9%) were from Iran, three from the UK, two from the USA, and two from Denmark. The remaining
articles were from Canada, Sweden, Italy, Spain, Japan, Indonesia, Portugal, the Netherlands, China, New
Zealand, and Norway. The total number of participants was 2,772, ranging from 13 to 343 per study (M =
95.6; SD = 88.3), with 1,374 undergoing ACT, ranging from six to 150 per study (M = 47.4; SD = 39.4).
Six studies were conducted in primary care, and 23 in hospitals, targeting both sexes and diverse health
conditions. ACT was used in combination with other interventions in 14 studies. A total of 111 dependent
variables, 81 standardized measurement instruments, 14 physiological measures, medical records, and
non-standardized questionnaires were employed. Fourteen quasi-experimental trials were conducted, ten
of which had control groups, and 15 were randomized clinical trials. In five studies, ACT was directly
compared with other active treatments. Reported results were mixed, with some positive and others
neutral outcomes, but no negative results, and at least equivalent to other interventions. Methodological
quality varied among articles, and several limitations affecting validity and generalizability were
observed: limited studies, small sample sizes, non-accounting for dropouts, brief or nonexistent follow-up,
non-random sampling, high risk of biases, lack of intervention integrity control, high reliance on selfreports, and scant details on therapeutic procedures. In conclusion, ACT has been used as an intervention
in hospital and primary care settings, but the considerable variability in its implementation suggests that
this usage is still in an exploratory phase. Further studies with higher methodological quality on this topic
are desirable.