What Causes Depression and Anxiety Disorders?
Depression and anxiety are the most common of all mental illnesses, the services for which continue to grow faster than the rate of population growth. Depression and anxiety can often be managed in the general practitioner’s office, and they are the fourth most common problems brought to general practitioners. People who have either condition are often dealing with physical problems as well.
While it is not possible to say precisely which factors have contributed to mental health problems in the case of any given individual, experts generally agree that depression and anxiety disorders stem from some combination of biological/physical, psychological and social factors. In this article, we review some of these factors, and offer you references for further readings in this area.
Family studies show that the rate in first-degree relatives of individuals with mood disorder is consistently about two to three times greater than in families without depressed members. Supportively, in twin studies, identical twins were more than twice as likely as fraternal twins to have co-occurring depression (McGaffin, P., Rijsdik, F., Andrew, M., Sham, P., Katz, R., & Cardno, A., 2003).
If someone has had chronic physical disease problems such as coronary heart disease, diabetes, asthma, or chronic obstructive pulmonary disease, they carry an increased risk of depression and anxiety disorders (Haddad et al, 2010).
Neurochemical and/or hormonal imbalance
An imbalance in brain chemicals and/or the lack of availability of dopamine and serotonin (the “feel-good” neurotransmitters) in the brain can trigger a depressive episode, as can endocrine disorders such as hyperthyroidism or hypothyroidism (Hansel, J., & Damour, L., 2005).
Psychological factors contribute to the development of depression in 60 to 80 per cent of cases (Barlow, D.H., & Durand, V.M. (2005). Probably the most potent factor leading to a depressive episode or anxiety disorder is if someone has:
- Past history of depression and/or anxiety
- Someone who has had one or two episodes of major depression is at high risk of relapse and recurrence (Haddad et al, 2010).
Otherwise, mental health experts recognise four clusters:
Stressful life events
Difficult life events take their toll by greatly increasing the risk for depression and anxiety. These include most psycho-social triggers, such as bereavement, unemployment (especially if ongoing for some time), homelessness, poverty, debt, or abuse (Haddad et al, 2010).
When dogs, rats, and human beings in the laboratory were presented with unpleasant stimuli (such as electric shocks) that they could not control, they “learned” that they were helpless. Even when the experimental conditions were later changed and the subjects (whether animal or human) could terminate or avoid the stressor (the shock or whatever unpleasant stimulus they were being administered), they did not take steps to do so, as they had “learned” that nothing they did caused any changes; most of the subjects showed signs of depression. These findings evolved into the learned helplessness theory of depression (Seligman, M., 1975).
Negative cognitive styles
Beck (1967) noticed that some people depress themselves by interpreting everyday events in a negative way. He referred to this tendency to view themselves, the world around them, and the future in a pessimistic way as a “negative cognitive style.”
Worry about anxiety/panic
Technically a “negative cognitive style” but deserving mention in its own right is the anxiety disorder that gets triggered after someone has already had a panic attack. Because the person worries about having another one, the “fight or flight” response is easily evoked. More and more stimuli (life situations) begin to remind the person of the original trigger for the panic. In trying to avoid the situations, the person is constantly engulfed in worry, leading to chronic anxiety.
Anxiety and depression disorders are diagnosed about twice as often in women as in men; some mental health experts have suggested that that may be because women have a greater tendency to seek help (Haddad et al, 2010). Australian statistics on completed suicide would tend to support that idea, in that about four times as many men as women complete a suicide attempt (Beyond Blue, Ltd., undated).
Mental health problems are more common among people at the lowest socioeconomic level.
Some ethnic groups are more likely to experience depression than members of the general population. An example is South Asian women in England.
As noted above, this is particularly linked with anxiety disorders.
Antenatal and postnatal period
Both before and after giving birth, there is increased risk for depressive symptoms (Haddad et al, 2010).
Links for further reading
Following is a list of further readings on depression and anxiety, available via the AIPC Article Library. Click each link to access the article.
- What is Anxiety?
- Psychological Treatment for Anxiety Disorders
- Treating Anxiety with CBT: The Evidence
- Motivational Interviewing and Anxiety
- Social Anxiety Disorder: The Core Patterns and Symptoms
- Depression and Depression Disorders
- Psychological Interventions for Depression
- The Efficacy of CBT Treatment for Depression
- Postnatal Depression: Onset, Prevalence and Consequences
- Depression in Older Adults: What Does It Look Like?
- What Causes Depression in the Elderly?
- Treatment Options for the Depressed Elderly
- Australian Institute of Health and Welfare (AIWH). (2010). Mental health services in Australia 2007-2008. Mental health series no. 12. Cat. No. HSE 88. Canberra: AIHW.
- Barlow, D.H., & Durand, V.M. (2005). Abnormal psychology: An integrative approach. Belmont,
CA: Thomson Wadsworth.
- Haddad, M., Buszewicz, M., & Murphy, B. (2010). Supporting people with depression and anxiety: A guide for practice nurses. University College London, MRC General Practice Research Framework.