A Better Way to Measure Antidepressant Response?

Health News,

New research calls into question the established method of assessing patient response to antidepressant treatment and expands the concepts of “responder” and “nonresponder.”

Investigators assessed more than 800 patients with major depressive disorder (MDD) attending a partial hospital program. The patients completed questionnaires about depressive symptoms as well as functioning and broader measures of quality of life (QoL).

Although fewer than 40% were classified as treatment responders on the basis of depressive symptoms, as measured by the Remission from Depression Questionnaire (RDQ), two thirds met criteria as responders on the Patient Global Rating of Improvement (PGI) scale, which takes into consideration broader domains of life satisfaction.

“The treatments we’re offering patients may be doing a better job than we think in treating depression, because many patients say they feel significantly better, even if their depression symptoms haven’t been diminished by the arbitrary threshold of 50% or greater improvement,” study investigator Mark Zimmerman, MD, professor of psychiatry and human behavior, Brown University, Providence, Rhode Island, told Medscape Medical News.

“Many of these patients — even if they have ongoing depressive symptoms — nevertheless say treatment has been very or extremely helpful, which is picked by other emphasizes in outcome, such as functioning, quality of life, coping abilities, and positive mental health,” added Zimmerman, director of the Outpatient Division at the Partial Hospital Program, Rhode Island Hospital.

The study was published online August 1 in the Annals of Clinical Psychiatry.

What’s the Best Tool?

“Almost all studies of depression treatment rely on measures of symptom severity to evaluate outcome — which is understandable, because a diagnosis of MDD requires a minimum number of symptoms for a sustained period of time,” said Zimmerman.

However, while important, symptom reduction is only one component of depression treatment. Improving overall function, QoL, and ability to deal with life’s stressors are equally important, he said.

Zimmerman emphasized he’s an “advocate, supporter, and practitioner of measurement-based care.” This approach, he said, “increases efficiency of the visit and directs me to the areas I should be inquiring about and the areas that need less time for inquiry.”

Measurement tools also enable numerical documentation of how a patient is doing and helps them understand and recognize their improvement.

The question is which tool captures improvements most effectively. Several surveys show that patients value improved functioning and QoL as primary treatment goals, which “is different from the emphasis of symptom improvement found in research,” said Zimmerman.

A multidimensional questionnaire that assesses functioning, QoL, and coping ability as well as symptoms is more likely to reflect patients’ treatment goals than simply measuring symptoms, he said.

Zimmerman and his co-author reported on findings from the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) Project, which “examined the concordance between patients’ global rating of improvement from treatment and responder status, based on a depression symptoms severity scale.”

Doing Better Than We Think

The study was conducted in Rhode Island Hospital’s Department of Psychiatry partial hospital program, where 844 patients with MDD (65.2% women; mean [SD] age, 36.8 [13.9] years) completed the RDQ — a self-report measure that “assesses constructs that patients consider to be relevant for assessing treatment outcome.” This questionnaire assesses symptom and non-symptom domains that people consider important when evaluating treatment effectiveness.

To the original 41-item questionnaire, the researchers added 19 items. The final 60-item questionnaire included the following:

  • 14 depressive symptoms

  • 11 nondepressive symptoms

  • 5 coping ability/stress tolerance items (eg, “I had trouble handling pressure”)

  • 12 positive mental health items (eg, “I saw myself as a person of value”)

  • 10 functioning items (eg, “I was socially withdrawn”)

  • 8 general well-being/life satisfaction items (eg, “I was engaging in life rather than hiding from it”)

Patients were divided into three groups:

  • Symptom responders (whose scores on the RDQ depressive symptom subscale improved by ≥50% from admission to discharge)

  • PGI responders, who weren’t symptom responders — ie, who reported global improvement but didn’t improve ≥50% on the depression symptom subscale

  • Nonresponders (ie, patients who didn’t respond on the PGI and the depressive symptom subscale)

The researchers compared the three groups on the four symptom domains of the RDQ. Patients also completed the PGI on discharge, and the researchers compared these responses to responses to the RDQ.

Only 38.7% were responders on the depressive symptoms subscale, while 67.4% were PGI responders.

Most patients (91.4%) who were responders on the depressive symptom subscale were also PGI responders, while 32% were PGI responders but not responders on the depressive symptom subscale.

Although 29.2% were nonresponders on both measures, 70.8% were responders on one scale or the other.

As far as the non-symptom domains, response rates varied between 30% (life satisfaction) to 33.1% (positive mental health).

“If you’re using a measurement tool in practice, I’d recommend one that goes beyond symptom improvement and also captures broader domains,” Zimmerman said.

“Better Enough”

Commenting for Medscape Medical News, Philip Muskin, MD, professor of psychiatry, Columbia University Medical Center, New York City, said the use of symptom-driven rating scales to measure depression response originated in mandates of the US Food and Drug Administration to determine whether a drug being tested in a clinical trial is superior to placebo.

“But there has been, for a long time, the question of whether these people are really better,” said Muskin, who was not involved with the current study. “Symptomatically, they may show improvement, but do they actually perceive themselves as better?”

Some patients might report, “I’m about 75% myself, but not back to 100%.” Muskin doesn’t “take these to be hard-and-fast numbers, but patients can tell you how they perceive themselves. This study suggests that if you’re wedded to [symptom measurement] scales, you may not realize that patients are actually getting better. And who decides if a patient is better, or better enough? The patient decides that.”

He added that some patients won’t achieve complete remission. “Even if I can’t get the person to be 100% better, I’m glad if I can help them become ‘better enough’ to function in life, do things, go to work, and improve in quality-of-life domains.”

The study received no outside funding. Zimmerman and his co-author and Muskin report no relevant financial relationships.

Ann Clin Psychiatry. Published online August 2, 2023. Abstract

Batya Swift Yasgur MA, LSW is a freelance writer with a counseling practice in Teaneck, NJ. She is a regular contributor to numerous medical publications, including Medscape and WebMD, and is the author of several consumer-oriented health books as well as Behind the Burqa: Our Lives in Afghanistan and How We Escaped to Freedom (the memoir of two brave Afghan sisters who told her their story).

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