Psychological Treatments

SCP has led efforts to identify and share empirically supported psychological treatments. While both the Chambless and Tolin criteria were designed specifically for psychological interventions, they lacked an operational definition of “psychological treatment” until 2023. This gap risked including non-psychological practices (e.g., pharmacology, exercise, brain stimulation) or pseudoscientific practices that may show statistical effects in RCTs but for reasons not based on psychological principles. To address this, SCP convened an expert task force to define psychological treatment through a rigorous process involving literature review, meetings, and public commentary.

The task force concluded with the following operational definition:

A psychological treatment is an intervention consisting of specific actions between a person or persons and a mental health professional or designee, with the intent of engaging cognitive, emotional, behavioral, or interpersonal processes, in the service of modifying health or functional outcomes, and whose core assumptions about its procedures and mechanisms of change are founded in psychological science and consistent with scientific understanding.

An intervention consisting of specific actions: Here, psychological treatment is characterized, in part, as specific, planned actions. This characterization helps differentiate psychological treatment from the broader practice of psychotherapy.

between a person or persons and a mental health professional or designee: There may be one or many recipients of a psychological treatment, such as in individual, couples, family, or group treatment. The definition does not require that the person delivering the treatment be a psychologist, nor is it assumed that if a psychologist is delivering the treatment it must therefore be psychological. It is acknowledged that in some jurisdictions the term “psychological” is reserved for the actions of psychologists, and that practice is not emulated here. In addition, a mental health professional might designate another individual to carry out the intervention, such as when laypersons are trained to deliver specific treatments. The change in provider from (for example) a psychologist to a trained layperson does not mean that the treatment is no longer psychological. Completely self-administered treatments, such as bibliotherapy, however, do not meet this criterion. The definition implies evaluating the process and outcome of the treatment and adjusting the treatment accordingly, which is not possible in many self-administered treatments such as bibliotherapy. While there is a developing realm of treatment delivered by computer programs, future SCP efforts might involve convening a separate working group to determine whether such computer programs should be considered a “designee.”

with the intent of engaging cognitive, emotional, behavioral, or interpersonal processes: This speaks to the issue of treatment mechanisms (not outcomes). Specifically, psychological treatments are posited to engage psychological processes. This differentiates psychological from (for example) medical treatments, which might strive to address the same outcomes, but via different (non-psychological) mechanisms.

in the service of modifying health or functional outcomes: This is the desired outcome (not mechanism). Although many of these health outcomes will be related to mental health conditions, the definition leaves room for psychological treatments that affect physical health, marital satisfaction, social functioning, and other outcomes.

and whose core assumptions about its procedures and mechanisms of change are founded in psychological science: Not all psychological treatments will be empirically derived or empirically supported, but the core assumptions about how the treatment works must be based on the science of psychology.

and consistent with scientific understanding: A psychological treatment cannot violate known scientific principles, either those from the science of psychology or those from other branches of science such as biology, chemistry, or physics.

Readers who wish to read more are encouraged to read A Proposed Definition of Psychological Treatment and Its Relation to Empirically Supported Treatments (Tolin et al., 2025) published in Clinical Psychology: Science and Practice.

The current list does not include all empirically supported treatments. Many were evaluated using the archived Chambless & Hollon (1998) criteria, which is not being updated. As a result, archived ratings (e.g., “modest” or “weak”) may not reflect more recent research.

In addition, some treatments with strong evidence are not included on this list. Absence from the list does not imply a lack of evidence or that no evidence-based treatments exist for a given diagnosis—it may simply mean the treatment has not yet been reviewed. Researchers interested in evaluating eligible psychological treatments (i.e., one that satisfies the aforementioned definition) are encouraged to learn more about the process here.

Previous Criteria (Chambless-Hollon,1998)

STRONG: Criteria are met for what Chambless & Hollon (1998)  termed “well-established” such that well-designed studies conducted by independent investigators converge to support a treatment’s efficacy. It is possible for this threshold to be met through a series of carefully controlled single-case studies.

MODEST: Criteria are met for what Chambless & Hollon (1998)  termed “probably efficacious treatments” such that one well-designed study or two or more adequately designed studies support a treatment’s efficacy. It is possible for this threshold to be met through a series of carefully controlled single-case studies.

CONTROVERSIAL: Studies of a given treatment yield conflicting results or if a treatment is efficacious but claims about why the treatment works are at odds with the research evidence.

Current Criteria (Tolin et al., 2015)

VERY STRONG: High quality evidence that treatment improves symptoms and functional outcomes at post-treatment and follow-up; little risk of harm; requires reasonable amount of resources; effective in non-research settings

STRONG: Moderate to high quality evidence that treatment improves symptoms or functional outcomes; not a high risk of harm; reasonable use of resources

WEAK: Low or very low quality evidence that treatment produces clinically meaningful effects on symptoms or functional outcomes, gains from the treatment may not warrant resources involved

INSUFFICIENT EVIDENCE: No meta-analytic study could be identified, or existing meta-analyses are not of sufficient quality.