The CODA Study

Short title: Feasibility Study in Comorbid Obesity and Treatment-Resistant Depression using Minocycline as Adjunctive Treatment (CODA)

We are investigating the feasibility, suitability, and acceptability of the use of an antibiotic medication called minocycline, which has broad anti-inflammatory properties, in people with both obesity and depression and elevated inflammation levels. This will be determined by looking at intervention adherence, recruitment rate, visit activity completion, and participant feedback.

Additionally, as a secondary aim, we will investigate the biological/inflammatory effects of minocycline at the body and at the brain level in people with comorbid obesity and depression who are not responding well to their anti-depressant treatment. By understanding how this drug works, we can find new ways to help those with depression who are not responding well enough to their current anti-depressants.

For more information, email us at coda@kcl.ac.uk

Recruitment: Open

Research/Analysis: Ongoing

What’s involved?

• 8 weeks of daily treatment with minocycline

• 4 in-person visits at King’s College Hospital, and 1 telephone interview

• 2 brain scans

Who can take part?

• Age 18-65 years

• Currently experiencing symptoms of depression

• Body Mass Index ≥30 kg/m²

• Lack of response to two different antidepressants

What is the purpose of the project?

Scientists have found that the immune system – the body’s system dedicated to fighting infections – is in a state of “hyperactivity” (i.e., more active than you would normally expect) in some people with depression, despite the lack of any actual ongoing infection. This response is referred to as inflammation. This discovery has unveiled unique opportunities to identify new medications to help patients with this heightened inflammation who have also not been responding to their antidepressant medications. What we have yet to understand clearly is how a medication with anti-inflammatory properties, may boost anti-depressants’ effects.

Obesity and depression often co-occur, with roughly 30% of individuals with obesity also having a diagnosis of depression. One suggested mechanism behind this co-occurrence is “hyperactivity” of the immune system. Recent research has shown that the co-occurrence of depression and obesity in an individual increases the risk of heightened inflammation. Increased inflammation has also been shown in the brain in people with depression. Scientists have found that neuroinflammation (inflammation in the brain) impacts brain structure in people with both depression and people with obesity, which can impact their learning and memory.

This study aims to investigate the feasibility of whether individuals with both obesity and depression will complete an 8-week course of minocycline, an antibiotic with anti-inflammatory properties, alongside their regular anti-depressant medication. Likewise, we want to understand if participants are able to complete blood and saliva sample measurements, undergo 2 brain scans, and complete interviews and questionnaires over the course of 5 visits (12 weeks total).