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Depression is a common mental health condition that affects millions of people worldwide. While traditional antidepressants can be effective, they can also take weeks to start working and may not be effective for all patients. Ketamine, a drug originally used for anesthesia, has emerged as a potential treatment for depression, particularly in cases where other treatments have failed. In this blog, we will explore the efficacy of single and repeated administration of ketamine in unipolar and bipolar depression based on a meta-analysis of randomized clinical trials.

The Meta-Analysis

A systematic review and meta-analysis of 33 randomized clinical trials involving 1,229 patients with unipolar and bipolar depression was conducted to evaluate the efficacy of ketamine in treating depression. The study included trials that used either single or repeated administration of ketamine.

Results showed that both single and repeated administration of ketamine were effective in reducing depressive symptoms compared to placebo. However, the response rate was higher in the repeated administration group, with 62.1% of patients experiencing a significant reduction in symptoms, compared to 49.7% of patients in the single administration group. Additionally, the effect size was larger in the repeated administration group, indicating that repeated administration of ketamine may be more effective in treating depression.

Interestingly, the study also found that the antidepressant effects of ketamine lasted longer after repeated administration compared to a single administration. This suggests that repeated administration of ketamine may have a lasting effect on depression symptoms.

Unipolar vs. Bipolar Depression

The meta-analysis also looked at the efficacy of ketamine in treating unipolar and bipolar depression separately. Results showed that both forms of depression responded well to ketamine treatment. However, the response rate was slightly higher in patients with unipolar depression compared to bipolar depression. This suggests that ketamine may be a more effective treatment for unipolar depression, although further research is needed to confirm this finding.

Side Effects

While ketamine has shown promise as a treatment for depression, it can also cause side effects. The most common side effects reported in the studies included in the meta-analysis were dissociation, dizziness, and headache. These side effects were generally mild and short-lived, and no serious adverse events were reported. 

The Benefits of Ketamine for Unipolar & Bipolar Depression

Ketamine has shown promising results in the treatment of both unipolar and bipolar depression. Here are some of the benefits of ketamine’s effectiveness in treating these types of depression:

Rapid onset of action

Unlike traditional antidepressants, which can take weeks or even months to take effect, ketamine has a rapid onset of action. Many patients report feeling better within hours or days of receiving ketamine treatment. This rapid response can be especially beneficial for patients who are in a crisis and need immediate relief from their depression symptoms.

Improved treatment response

Research has shown that up to 70% of patients with treatment-resistant depression (TRD) respond to ketamine treatment. This is significant, as TRD is a condition in which patients do not respond to traditional antidepressant treatments. Ketamine can be a powerful tool for these patients who have not found relief with other treatments.

Reduced suicidal ideation

One of the most dangerous symptoms of depression is suicidal ideation. Ketamine has been shown to rapidly reduce suicidal thoughts and behaviors in patients with depression. This can be lifesaving for patients who are experiencing acute suicidal ideation. 

Long-lasting effects

Although the effects of a single ketamine treatment may only last for a few days to a few weeks, studies have shown that repeated treatments can have long-lasting effects on depression symptoms. This means that ketamine can be an effective long-term treatment option for patients with depression.

Fewer side effects

Traditional antidepressants can cause a range of side effects, including weight gain, sexual dysfunction, and gastrointestinal problems. Ketamine, on the other hand, is generally well-tolerated and has fewer side effects. This can be particularly beneficial for patients who have not been able to tolerate other medications.


Ketamine has shown great promise in the treatment of both unipolar and bipolar depression. Its rapid onset of action, improved treatment response, reduced suicidal ideation, long-lasting effects, and fewer side effects make it an attractive option for patients who have not found relief with other treatments. However, it is important to note that ketamine should only be administered under the supervision of a trained medical professional, like Georgia Renew Clinics.