How Does Early-Onset Depression in Mothers Affect Their Daughters' Brain Response to Rewards?

What you need to know

• Mothers who develop depression before age 20 show reduced brain responses to rewards, which may make positive experiences less enjoyable
• Their never-depressed teenage daughters show similar patterns in brain activity, suggesting this trait can be passed down
• Understanding these brain patterns could help identify youth at risk for depression and lead to better prevention strategies

The Brain’s Reward System and Depression Risk

Think about the last time you won something or received good news. For most people, these moments trigger a surge of positive feelings and activation in the brain’s reward system. But for people with depression, this natural response can be dampened, making it harder to feel pleasure from normally enjoyable experiences.

New research suggests this reduced response to rewards may be passed down from mothers to daughters, particularly when mothers developed depression early in life. This finding helps explain why depression often runs in families and points to potential ways to identify and help those at risk.

How the Study Worked

Researchers recruited mothers with and without a history of depression, along with their teenage daughters who had never been depressed. The participants played a simple computer game where they could win small amounts of money while their brain activity was measured using electroencephalography (EEG), which records electrical signals from the brain.

The researchers focused on a specific brain response called the Reward Positivity (RewP), which happens about a quarter of a second after receiving a reward. The strength of this response indicates how sensitively someone’s brain reacts to positive experiences.

Key Findings About Mothers

The study found that mothers who had experienced depression at any point showed a reduced brain response to rewards compared to mothers who had never been depressed. However, this effect was particularly strong in mothers who developed depression before age 20 (called early-onset depression).

This suggests that early-onset depression may represent a distinct form of the illness with stronger biological roots that are more likely to be passed down to children. This aligns with previous research showing that early-onset depression tends to be more severe and run more strongly in families.

What This Means for Daughters

Perhaps most intriguingly, the teenage daughters of mothers with early-onset depression showed similar patterns of reduced reward response in their brains - even though they had never experienced depression themselves. This suggests they may have inherited a biological trait that could increase their risk for developing depression later.

This finding is particularly important because it shows these brain patterns exist before any symptoms of depression appear. This means they could be a marker of risk rather than just a consequence of being depressed.

What This Means for You

If you or someone in your family has experienced early-onset depression, this research highlights the importance of being proactive about mental health in the next generation. Some practical steps include:

• Being aware that depression risk can run in families, particularly through mothers to daughters
• Watching for early signs of reduced enjoyment or pleasure in activities
• Teaching coping skills and emotional awareness from an early age
• Seeking professional guidance if concerns arise
• Understanding that having risk factors doesn’t guarantee developing depression

Conclusions

• Early-onset depression appears to have stronger biological components that can be passed from mother to daughter
• Brain responses to rewards may be one way this risk is transmitted
• This knowledge could help identify at-risk youth before they develop symptoms