Early life adversity could make an individual more at risk of developing negative thinking, which could lead to major depressive disorder (MDD), says new research by the University of Bristol. The findings provide biological and psychological evidence to support work first proposed in the 1960s.
The study - using a rodent model of early life adversity - has shown that offspring are much more sensitive to negative biases in their cognition when treated with the stress hormone corticosterone. The research - published in Neuropsychopharmacology - showed that a dose of corticosterone had no effect in normal rats but caused a negative bias in the early life adversity animals. The study also found that the early life adversity rats were less likely to anticipate positive events and failed to properly learn about reward value. These impairments in reward-related cognition are particularly interesting as one of the main features of depression is a loss of interest in previously enjoyable activities. The findings support the idea that those at risk of developing mood disorders may have impairments in the way they learn about and use their memories about how rewarding an experience has been to then guide and motivate them to repeat the activity.
The researchers suggest that these neuropsychological effects might explain why early life adversity can make people more likely to develop depression. "This study supports a wider body of literature which suggests that depression may develop from an interesting yet complex interaction between biological and psychological processes,” says Emma Robinson, Professor of Psychopharmacology, School of Physiology, Pharmacology & Neuroscience and lead author on the paper. “As we start to understand these better we hope that the knowledge we generate can be used to better guide current and future treatments. Our larger body of work suggests that the effectiveness of current antidepressant treatments might be linked to how much a person is able to re-engage with their environment and their level of social support. The findings also add further evidence to support the validity of this relatively new area of research into mood disorders, particularly studies using animals to understand the neurobiology of affective biases and how they contribute to normal and pathological behavior."
Studies in patients have shown that depression is linked to changes in how the person processes information - particularly emotional information. People with depression have a negative view of the world which can be measured by looking at how they process information such as emotional faces and words. However, whether this causes the illness or are a consequence is not known. The researchers developed a method to use in rodents where similar neuropsychological processes were measured. One of the tasks, the affective bias test, looked at how simple associations between a specific cue, a bowl with a specific digging substrate in it, and a reward, a food pellet, could be biased by the animal's affective state when they learn about it.
When animals learn the association in a negative affective state they remember it in a more pessimistic way whilst memories formed in a positive affective state are remembered in a more positive way. The biases the study was able to measure in rodents correlated exactly with how these same treatments affect peoples' mood in the long-term, something which no other animal test in psychiatry has been able to achieve. The next step in the research will be to understand how these processes and the deficits seen in the animals respond to current antidepressant treatments including the recently licensed, rapid onset antidepressant ketamine. The researchers already have some evidence about how ketamine interacts with these neuropsychological processes and this latest work will help them bring these findings together with an important disease model and risk factor for depression.
Correlation Between Knee Pain And Depression
It has been long suspected that physical pain can have a hand in mental strife and unrest. When a person doesn't feel the best physically or is hindered in their abilities to function fully as they normally would, depression can be the result. This premise was proven in Japan when researchers studied the link between individuals who suffered from osteoarthritis in their knees and who also dealt with depression after its onset.
Over 550 people over the age of 65 took part in the Kurabuchi study. When the study began, no one had any symptoms of depression. However, two years later 12 percent of the participants had developed symptoms of depression.
The study showed that over 55 percent of individuals over the age of 40 dealt with some type of knee pain linked to osteoarthritis. This type of knee pain can lead to impaired knee function and impede the person's ability to complete certain tasks and activities.
The most common ways that this knee pain would show itself and impact these individuals would be when they were going to bed, lying in bed, putting on socks, and getting in and out of the car. When the knee is positioned a specific way and then must bend or undergo specific amounts of pressure, this can be incredibly painful and even impossible for knees riddled with osteoarthritis.
Researchers believe that asking people who do deal with certain amounts and levels of pain if they are experiencing symptoms of depression can go a long way in understanding the link between physical pain and mental unrest. Depression can exist as a byproduct of some type of event that takes place in a person's life; other times it can be from the constant and overwhelming instances where chronic physical pain is impacting their lives.
Rethinking Approach To Health
When we start to uncover the link between physical pain and mental pain, then perhaps the stigma of mental health difficulties can start to diminish. The fact that we understand and can treat and sympathize with someone who deals with chronic knee pain but not someone who struggles with depression or anxiety is where society needs to rethink our approach to health. Mental illness doesn't always have a very defined or easily attainable impetus, but what needs to take place as a result of its presence is clear, discernible action and support to help those who are impacted by it.
Some people don't even realize that they are dealing with mental illness. Whether it's intense mood swings, constant fear and worry or being in the depths of sadness with no end in sight, these things need to be taken seriously and help can be obtained. Whether it’s the rate of suicide or the amount of people that are coping with their pain and suffering in really unhealthy and dangerous ways, such as developing dependencies, addictions and poor habits just to have some relief from their own mind and thoughts.
The fact that mental health has such a stigma around the world makes it an area where we need to do more to ensure that anyone who feels hopeless, alone or afraid can feel seen and heard and given options to improve their life and thoughts. Mental health and properly treating it needs to be a top priority all over the planet.
Lisa S. Jones is a certified nurse, nutritionist, fitness coach and health expert. Her training credentials include a B.Sc. in Nursing from California State University in 2013 and Youth Nutrition Specialist Certification from the American Fitness Professionals and Associates in 2015. In 2017, she also received Holistic Nutrition Certification from the American Fitness Professionals and Associates.