What is the Success Rate in Treating Major Depressive Disorder?

Major depressive disorder affects more than 16 million Americans. It’s the leading cause of disability in the United States and has become one of the country’s most devastating mental health issues. While many treatment methods and medications exist to treat this disease, some cases are critical and require intensive intervention. 

Over the last two decades, researchers have studied ketamine as an antidepressant effective enough to treat patients with treatment-resistant major depressive disorder. Below are summaries of a few significant studies conducted to uncover ketamine’s success rate in its treatment. Read on to learn more.

72% Response Rate After 10 Infusions

The Journal of Clinical Psychiatry published a study from September 2022 in which researchers looked at data from 424 people throughout three Virginia-based ketamine infusion clinics. All patients were treated between November 2017 and May 2021 for treatment-resistant major depressive disorder, suicidal ideation, and anxiety. The patients filled out mental and physical health surveys during each treatment session. All patients received a total of six infusions throughout a 21-day course.

Half the patients responded to the treatment right away. After ten infusions, the response rate was 72%, and the remission rate was 38%. Half of the suicidal ideation patients went into remission after six weeks, meaning they no longer had those thoughts. The results also showed a reduction of 30% in anxiety symptoms throughout the treatment course. 

Overall, these results showed that ketamine treatment was highly effective at treating major depressive disorder, suicide ideation, and anxiety. Moreover, “the high rates of response and remission were similar to those for interventional treatments in community samples of TRD (treatment-resistant depression).”

Significant Improvements After One Hour, Two Weeks, One Month

In October 2019, the Indian Journal of Psychiatry published results from a study in which 25 male patients with severe major depressive disorder and no previous history of disorders, injuries, or substance abuse problems were admitted for the study. They received six doses of ketamine injections in the course of two weeks. The study results were concluded after one month had passed since the last treatment. 

The results showed a significant improvement in anxiety, major depressive disorder, and the severity of illness after two weeks and again after one month of the last treatment. The effects of the treatment were described as “rapid and robust”, with immediate effect that was sustained after a month.

73% Reduction in Suicidal Ideation

In March 2022, the Journal of Affective Disorders published results from a study that analyzed 9,016 major depressive disorder patients between 2016 and 2020. They all received a series of 4-8 ketamine infusion treatments over 7 to 28 days at one of 178 community practices across the country. The Patient Health Questionnaire-9 (PHQ-9) was used to evaluate their symptoms. 

According to the results, 53.6% of patients showed a response at 14–31 days after treatment, and 28.9% remitted. 73% of patients with suicidal ideation exhibited a reduction in symptoms. The durability of the response to the treatment was 60% after eight weeks.