Depression is a serious mental health condition that affects how people feel, think, and handle daily activities. When left untreated, depression can have long-lasting effects on the brain and overall health. Here is an overview of what happens in the brain when depression goes untreated:
Changes in Brain Structure
Studies using brain imaging techniques show that untreated depression is linked to changes in brain structure and function. These include:
- Shrinkage of the hippocampus – an area involved in learning, memory and emotional control
- Decreased activity in the prefrontal cortex – involved in complex cognitive functions like decision making
- Increased activity in the amygdala – processes emotions like fear and anxiety
These changes may persist even after depressive symptoms improve, especially with longer durations of untreated illness.
Decreased Neuroplasticity
Neuroplasticity refers to the brain’s ability to form new neural connections and adapt to challenges. This plasticity is critical for learning, memory and emotional regulation. Studies indicate depression leads to:
- Reduced neural growth factors like BDNF that support plasticity
- Fewer new neural connections in areas like the prefrontal cortex and hippocampus
- Impaired ability to make cognitive and emotional adaptations
Without treatment, these neuroplastic changes may not fully reverse even when the depression lifts.
Neurotransmitter Imbalances
Depression is associated with imbalances in neurotransmitters – chemicals that communicate information between brain cells. For example:
- Lower levels of serotonin, which regulates mood, sleep, appetite
- Lower dopamine, which affects motivation, pleasure and reward-seeking behaviors
- Higher cortisol, the stress hormone
Chronic neurotransmitter imbalances from untreated depression can disrupt many aspects of physical and mental health.
Inflammation
Growing evidence shows that depression is linked to chronic inflammation – the body’s immune response to harm. Possible sources include:
- High stress hormone levels
- Oxidative stress and free radical damage
- Dysfunction in microglia immune cells in the brain
- Autoimmunity
This inflammation may begin in the brain but spread systemically. It can lead to damage that persists even after depressive episodes end.
Neuron Death
In severe cases, the cumulative effects of untreated depression may include loss of neurons in key brain regions like the prefrontal cortex and hippocampus. Contributing factors include:
- Elevated stress hormones like cortisol and glutamate that are toxic at high levels
- Lack of growth factors needed for neuron health
- Reduced neural plasticity
- Chronic inflammation
Losing neurons can impair cognitive function and the ability to regulate mood long-term.
Brain Aging
The changes from untreated depression can accelerate biological aging processes in the brain such as:
- Oxidative stress
- Reduced telomere length on chromosomes
- Mitochondrial dysfunction
- Accumulation of proteins linked to neurodegeneration
This accelerated brain aging shows up on scans as loss of brain volume beyond normal age-related decline.
Cognitive Decline
Untreated depression takes a toll on cognitive abilities like:
- Memory
- Executive function – planning, focus, organization
- Processing speed
- Spatial abilities
- Verbal fluency
Research links longer depressive episodes with greater cognitive decline, especially in later life. Early treatment is key.
Recurrence
People who have had an episode of depression have a very high risk of the depression recurring and becoming a chronic condition. Contributing factors include:
- Incomplete recovery in brain structure and function
- Lingering inflammation
- Maladaptive neural pathways
- Ongoing psychosocial stressors
Studies show the longer depression goes untreated initially, the more likely it is to come back.
Other Physical Changes
Untreated depression worsens many other aspects of physical health including:
- Impaired immune response
- Higher inflammation
- Increased risk for heart disease, diabetes, obesity
- Hormonal imbalances
- Digestive issues
- Chronic pain conditions
- Sleep disturbances
There are bidirectional relationships between depression and many health conditions, which can reinforce each other over time without treatment.
Suicide Risk
The cumulative effects of untreated depression significantly increase the risk of suicide. Contributing factors include:
- Feelings of hopelessness and despair
- Cognitive rigidity and tunnel vision
- Lethargy and apathy
- Psychache and emotional anguish
- Impulsivity and risk taking
Studies show up to 15% of people with untreated severe depression will die by suicide. Early intervention is vital.
Conclusion
In summary, allowing depression to go untreated can set off a cascade of progressive changes in brain structure and function, biochemistry, systemic health, and risk for recurrence and suicide. However, many of these changes may be prevented through early diagnosis and treatment, which provides hope for recovery. Ongoing research continues to uncover more about the complex brain and body changes related to untreated depression to guide the development of life-saving treatment strategies.