Positive Affect Treatment Improves Clinical Status in Low Positive Affect

Key Takeaways

• Positive Affect Treatment was associated with better multivariate clinical status than the comparison psychotherapy.
• A between-group advantage was reported at 1 month and appeared to reflect depression and anxiety symptom change more than interviewer-rated anhedonia or self-reported positive affect.
• Several self-reported reward and threat measures mediated clinical change, while behavioral and physiological measures did not, and no serious adverse events were reported.

In a multisite randomized clinical trial, Positive Affect Treatment was associated with better multivariate clinical status than Negative Affect Treatment among 98 adults receiving telehealth psychotherapy. Participants had moderate to severe depression or anxiety with severely low positive affect and were assigned to 15 weekly individual sessions. The primary multivariate analysis favored Positive Affect Treatment, with b = -0.06; 95% CI, -0.11 to -0.01; P = .02; d = 0.27. This comparative benefit was observed in a sample selected for marked deficits in positive affect.

This assessor-blinded, parallel-group, multisite, 2-arm randomized clinical superiority trial used intent-to-treat analyses, recruited participants from December 2021 to January 2024, and ended follow-up in July 2024. Eligible adults were treatment-seeking and had severely low positive affect with moderate to severe depression or anxiety that impaired functioning. Randomization assigned 51 participants to Positive Affect Treatment and 47 to Negative Affect Treatment; mean age was 32.8 years, and 66.3% were female. Clinical status combined PANAS-P, interviewer-rated anhedonia, and DASS total score, with clinical and target measures collected before treatment, during treatment, after treatment, and at 1-month follow-up. The trial compared two mechanistically distinct psychotherapies delivered in 15 weekly individual telehealth sessions.

At 1 month, Positive Affect Treatment retained an advantage in clinical status over Negative Affect Treatment, with b = -0.21; 95% CI, -0.41 to -0.02; P = .04; d = 0.21. This overall advantage appeared to be driven mainly by the DASS-21 total score, which showed greater improvement with Positive Affect Treatment (b = 1.27; 95% CI, 0.61-1.93; P < .001; d = 0.55). No significant between-group differences were reported for interviewer-rated anhedonia, b = 0.16; 95% CI, -0.06 to 0.36; P = .15, or PANAS-P, b = -0.38; 95% CI, -0.87 to 0.10; P = .12. The clinical advantage therefore reflected symptom improvement more than change in the other two clinical-status components.

Reward anticipation-motivation and response to reward attainment increased over time in both groups, with no significant between-group differences. Across groups, over-time estimates were b = 0.02; 95% CI, 0.01-0.03; P < .001 for anticipation-motivation and b = 0.04; 95% CI, 0.01-0.06; P = .002 for attainment. Threat targets also declined over time in both groups; in primary analyses, the slope was steeper with Negative Affect Treatment, and the follow-up between-group difference was not significant. Six of seven self-reported reward and threat measures mediated clinical outcomes, whereas none of the behavioral or physiological measures did. The mediation analyses supported temporal ordering within the study but did not establish causality and provided limited evidence for intervention-specific mechanisms. The overall mechanistic signal was mixed and was concentrated in self-reported measures.

No serious adverse events were reported during the trial period. Credibility, fidelity, and alliance details were described in supplemental materials, and the trial was conducted and reported in accordance with CONSORT. These findings reflect adults treated virtually in this randomized telehealth comparison and remain specific to that trial population and delivery context.