What causes mental illness?

While I can’t give you all the answers, take a look at this model which helps in identifying and treating mental illness.

The Diagnostic and Statistical Manual of Mental Disorder, Fifth Edition, has defined depression as 5 or more of the following symptoms that are present for 2 or more weeks and cause significant emotional distress and/or impairment in functioning:

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  1. depressed or sad mood
  2. short-tempered or easily annoyed
  3. loss of interest or enjoyment in hobbies or activities that was previously enjoyed
  4. feeling of worthlessness or guilt
  5. thoughts of death or suicide
  6. difficulty with concentrating or making decisions
  7. feeling tired or fatigue
  8. feeling restless or slow
  9. changes in appetite such as overeating or loss of appetite
  10. changes in weight such as weight loss or weight gain, and changes in sleep pattern.1 

According to the National Institute of Mental Health, depression occurs due to a combination of genetic, biological, environmental, and psychological factors.2

Genetic vulnerability refers to the inherited characteristics passed on from parents to children that make it more likely that a person will develop a mental illness or addiction.

Biological theory suggests that depression is caused by an imbalance of naturally occurring substances called neurotransmitters (Serotonin and norepinephrine) in the brain and spinal cord.

Depression is said to be almost twice as likely to affect women than men and tends to have different contributing causes in women than it does in men. Contributing factors include reproductive hormones (biological)

Psychological and environmental/social factors—such as lifestyle choices ie too much alcohol, past trauma, low self-esteem, substance abuse and loneliness can also play an enormous part in depression.

Treatment for depression consists of participation in psychotherapy, taking antidepressants, or a combination of both. However, many individuals don’t participate in psychotherapy or antidepressants due to factors such as side effects, lack of access/resource, or personal choice.

According to Agius et al 2010, the Stress Vulnerability Model is an extremely useful model for identifying and treating relapses of mental illness. We accept that humans carry genetic and other predisposition to mental illness. However, the question arises as to how stress impacts on a person in order to cause mental illness to develop. Furthermore there arises the issue as to what other effects such stress has on the human body beyond the human brain. 4.

The Stress Vulnerability Model explores the interrelationship between all these factors, and the genetic component which in large part constitutes the ‘vulnerability’ part of the model. Such problems occur in many Psychiatric illnesses, including Depression, PTSD, as well as Schizophrenia.

Vulnerability Factors predispose individuals to develop mental health problems e.g psychosis, clinical depression. Problems are triggered by stress. If vulnerability is high, low levels of environmental stress may trigger distress. Use and effectiveness of coping strategies goes some way to explain why some have problems and others don’t.

Let’s take a look at the model and I’ll share how my vulnerability lead to a psychotic depression:

Look along the bottom where it says Vulnerability – high to low. For me, because mental illness runs in the family (genetic) I have a predisposition to mental illness. I grew up with mum as single carer for four children, I was shy and had low self-esteem (psychological). We moved a lot, I went to more than ten schools and each time I was bullied because of my new accents (social/environmental), then there’s the childhood abuse (psychological), so — I have a high vulnerability to mental illness.

Now look at the left-hand side where it says stressful events: my ex had a baby with someone else, then the breakdown of my relationship, my ex was cheating, I experienced domestic violence, one of his girlfriend’s plagued me for eighteen months, I wasn’t sleeping, I felt suicidal, I was now a single parent and didn’t have any real coping mechanisms other than to bottle it all up. Therefore, you can add up all the stressful events and my arrow is very high, as in the diagram.

Follow that curve in the model and you’ll see how I have an extremely low stress threshold towards mental illness. Hence my psychotic depression, anxiety, panic attacks and anorexia.

While I still have a predisposition to mental illness, there’s been a huge reduction in my stressful events so I now have a higher threshold for stress.

So, back to the chart — Along the bottom line, I’m at the end, on the right ‘high vulnerability’. But along the left side, I’m presently low down on the scale as I have minimum stress at the moment (trace along the chart with your finger). So you’ll see, I’m currently in the mental health category, rather than mental ill-health.

Is this your empty toolbox? Photo by worthpoint.com

I still experience depression and anxiety but they tend to be reactive. I still take medication and I have an extensive toolbox of coping techniques that I can use, when necessary.

I found this model really helpful when working with patients and they liked how it might explain why they developed a mental illness. If you have a mental illness and you wonder why, try using the above chart to see if it’s helpful in determining the how or the why me?

Does this model fit with your ideas? Where would you sit on the graph? Do you think vulnerability needs more explanation? I’d really appreciate your thoughts.