How Does Cell Division Differ in People with OCD?

What you need to know

• This study found differences in cell division processes between people with obsessive-compulsive disorder (OCD) and healthy controls.
• Cells from people with OCD showed reduced cell division and growth compared to controls.
• The findings suggest abnormal cell cycle regulation may be part of the underlying biology of OCD.
• This research could potentially lead to new ways to diagnose or treat OCD in the future.

Understanding OCD and the search for biological markers

Obsessive-compulsive disorder (OCD) is a mental health condition that affects about 2% of people. It involves intrusive, unwanted thoughts (obsessions) and repetitive behaviors or mental acts (compulsions) that a person feels compelled to perform. While we can diagnose OCD based on symptoms, researchers are working to find biological markers - measurable signs in the body that could help identify the disorder.

One area scientists are exploring is how basic cellular processes may differ in people with OCD. This study looked specifically at the cell cycle - the series of steps cells go through when they divide and grow. Understanding if there are differences at this fundamental biological level could provide new insights into OCD.

How researchers studied cell division in OCD

To study cell division processes, the researchers used a type of white blood cell called lymphocytes. They collected blood samples from 11 people diagnosed with OCD and 8 healthy volunteers without OCD to serve as a comparison group.

From these blood samples, they created cell lines that could be grown and studied in the lab. These are called lymphoblastoid cell lines (LCLs). Using LCLs allows researchers to have an ongoing supply of cells to work with, rather than needing repeated blood draws.

The scientists then used a technique called flow cytometry to analyze what stage of the cell division cycle the cells were in. Flow cytometry uses lasers to detect characteristics of individual cells in a sample. This allowed them to determine what percentage of cells were in each phase of the cell cycle.

Key findings on cell cycle differences in OCD

When comparing the OCD and control groups, the researchers found a key difference in the percentage of cells in a particular stage of the cell cycle called the G2/M phase. This is the phase right before and during cell division.

Cells from people with OCD had a significantly lower percentage of cells in the G2/M phase compared to cells from the control group. On average, about 11.8% of cells from people with OCD were in G2/M phase, versus 14.1% for the control group.

This suggests that cells from people with OCD may have reduced cell division and growth compared to cells from people without OCD. The researchers describe this as “cell cycle arrest” - the cells seem to get stuck and have trouble progressing through the normal division process.

Interestingly, the researchers also looked at differences between people with OCD who responded well to common medication treatments versus those who did not respond well. They found that cells from people who did not respond well to medication had an even lower percentage of cells in the G2/M phase compared to those who did respond to treatment.

What could these cell cycle differences mean?

Finding differences in basic cellular processes between people with and without OCD is intriguing to researchers. It suggests that some of the underlying biology of OCD may involve disruptions to normal cell growth and division.

However, it’s important to note that this study looked at white blood cells, not brain cells. So how might findings in blood cells relate to a disorder that affects the brain? There are a few possibilities:

1. The cell cycle differences may reflect a broader issue affecting cells throughout the body, including in the brain.

2. There may be similar disruptions happening in brain cells that this study couldn’t measure directly.

3. The findings in blood cells may be indirectly related to brain function through the connections between the immune system and the brain.

More research is needed to understand the exact relationship. But finding measurable differences at the cellular level is a step toward potential biological markers for OCD.

Connecting cell cycle to other research on OCD

While this is the first study to look specifically at cell cycle in OCD, the findings connect to other areas of OCD research:

Oxidative stress: Previous studies have found signs of oxidative stress - a type of cellular damage - in blood samples from people with OCD. The researchers note that oxidative stress can cause DNA damage, which could potentially explain the cell cycle arrest they observed.

Genetic factors: OCD tends to run in families, suggesting genetic risk factors. Some of the genes that have been linked to increased OCD risk are involved in regulating the cell cycle. This study’s findings align with the idea that cell cycle disruption may play a role in OCD.

Overlap with other disorders: Abnormalities in cell cycle regulation have been found in studies of other psychiatric disorders like depression, schizophrenia, and bipolar disorder. This adds to evidence that there may be some shared underlying biology across different mental health conditions.

Effects of medication on cell cycle

The researchers also tested how a common OCD medication, fluoxetine, affected the cell cycle in the lab. Fluoxetine is a type of antidepressant called a selective serotonin reuptake inhibitor (SSRI).

They found that treating the cells with fluoxetine led to an overall reduction in the percentage of cells in the G2/M phase for both the OCD and control groups. This aligns with previous research showing that SSRIs can affect cell growth.

However, the effect of fluoxetine treatment in the lab didn’t differ between cells from people with OCD versus controls. This suggests the medication’s impact on cell cycle may be separate from its therapeutic effects in treating OCD symptoms.

Limitations and next steps

As with any scientific study, there are some limitations to keep in mind:

• The study had a relatively small sample size of 11 people with OCD and 8 controls. Larger studies will be needed to confirm the findings.

• The study looked at white blood cells rather than brain cells. While this provides useful information, it may not fully capture what’s happening in the brain in OCD.

• Most of the participants with OCD were already being treated with medications, which could have affected the results.

The researchers suggest several directions for future studies:

• Examining cell cycle regulation in larger groups of people with OCD, including those who haven’t started treatment yet.

• Looking at whether the cell cycle differences correlate with specific OCD symptoms or severity.

• Investigating the molecular mechanisms behind the cell cycle disruptions to better understand what’s driving the changes.

• Exploring whether medications other than fluoxetine have similar or different effects on the cell cycle in OCD.

Conclusions

• This study found differences in cell division processes between people with OCD and those without, specifically a reduction in cells undergoing division.
• The findings suggest abnormal cell cycle regulation may be part of the underlying biology of OCD.
• More research is needed to understand how these cellular changes relate to OCD symptoms and brain function.
• In the future, measures of cell cycle regulation could potentially serve as biological markers to aid in diagnosing or treating OCD.