A person may be depressed if, for more than two weeks, they have experienced either (or both) of the following¹:

• a sense of sadness, emptiness or low mood for most of the day, nearly every day
• a loss of interest or pleasure in almost all activities, even ones usually enjoyed.

For a diagnosis of depression, a psychologist will look for specific symptoms that impact on a person’s daily life. Some of these include changes to their appetite and sleep, lethargy, worry and negative thinking patterns.

There is no single cause for depression. In some individuals, stressful life events such as the loss of a job, long-term unemployment, physical health issues, family problems, the death of a loved one, or the end of a close relationship might trigger depression. For other people, there is no obvious cause.

Experts no longer believe that depression is caused by a ‘chemical imbalance’, but that the risk for developing depression is more likely to be related to a combination of a person’s genes, biology, life experiences, stress and thinking style.²

Genes

For many people, genetics may play a part, with research suggesting around 30-40% of the risk for developing depression may be due to genetic factors.^3-5

Biology

Research has found some differences in areas of the brain, and brain activity in people with depression compared to people without. The areas of the brain that differ relate to emotional responses and emotion regulation, the interpretation of information (with a bias for negative information) and response to stress. Interestingly, many of these differences decrease with treatment.⁶

Stressful life events

Research suggests that the greater the number of stressful live events a person experiences, the greater their chances of developing depression.⁷ Early life stress and trauma can also increase the likelihood of developing depression later in life.^8,9

Thinking style

People who tend to dwell on negative events, worry excessively, or hold a more negative view of themselves, the world, or the future are more prone to depression.^10-13

Check your self-talk

We can sometimes say negative things to ourselves when we are upset. Unhelpful self-talk might include things like, “I’m hopeless”, “Why should I even bother?”, or “I’ll never get all this work done”. Negative self-talk can make our mood worse by reinforcing how bad we feel, and stopping us from using helpful coping strategies. Constructive self-talk, on the other hand, can help us to cope with life’s difficulties.

Notice what you say to yourself and work on more helpful, calming and encouraging self-talk, such as, “This is a rough period but it will pass”, “I will use this time to look after myself”, or “Regardless of how I am feeling, I am always a worthy person”.

Keep things in perspective

When we are upset, it is easy to see things as worse than they really are, and to start anticipating even more problems down the track. Take a step back and look at something that is upsetting you. Ask yourself:

• am I getting ahead of myself, assuming something bad will happen when I really don’t know the outcome?
• is the outcome certain to happen, possible, or quite unlikely?
• if the worst were to happen, what could I do about it?

Sometimes thinking about how you would cope, even if the worst were to happen, puts things into perspective.

Get active

Make a list of things that you usually enjoy. It might include activities like light exercise, reading, meditating, listening to music, or spending time with a friend. Then, write down a list of things that are important to you that would give you a sense of achievement – things that would feel good to get done. This might include household chores, errands, work tasks or study. Now, take your weekly schedule and make time each day to attend to a task from each list. It is important to set realistic goals and then work towards achieving them.

Practise relaxation or mindfulness

Practise relaxation, meditation, or mindfulness on a regular basis to allow your body and nervous system to routinely settle and readjust to a calm state. Mindfulness in particular has been shown to help people to respond to difficult emotions without feeling overwhelmed by them.

Look after your health

Exercise, diet and other health behaviours can support recovery from depression, so it is important to:

• make sure you are eating well
• get regular exercise
• avoid using alcohol, tobacco and other drugs to cope when you are finding things difficult.

Depression is a common reason for people to seek help from mental health professionals, and research suggests that there are a number of effective psychological treatments available. The most effective psychological treatments for depression are cognitive behavioural therapy, problem-solving therapy, behavioural activation and interpersonal psychotherapy. Mindfulness-based cognitive therapy has also been shown to be effective in preventing future periods of depression in those people who have previously experienced depression.¹⁴

Cognitive behaviour therapy (CBT) can bring about lasting change that can decrease the chance of having depression again in the future. It helps the person to change unhelpful thoughts and behaviours which can contribute to depression, and aims to build skills to manage depression in an ongoing way.^15-17

Problem-solving therapy helps people gain mastery over day-to-day difficulties, stresses and problems which otherwise might seem overwhelming.^{15, 18}

Behavioural activation aims to increase motivation and help a person to return to their usual activities. In behavioural activation, activities and behaviours that can help to improve mood and quality of life are planned for in an ‘activity schedule’. Typically, a mix of activities are selected including some which the person finds enjoyable and some which give them a sense of satisfaction and achievement.^{15, 19, 20}

Interpersonal psychotherapy (IPT) involves addressing problems in the person’s relationships and expectations about others that might be contributing to their mood. IPT helps people to:

• find new ways to develop and nurture relationships
• resolve conflicts with others
• express emotions and communicate more effectively
• adapt to changes in life roles
• improve social support networks.^{15, 21}

Mindfulness-based cognitive therapy (MBCT) is an eight-week group-based program designed to reduce the risk of depression returning (relapse prevention), by teaching participants mindfulness meditation combined with cognitive-behavioural techniques.^{14, 22}

Mindfulness meditation helps the person to focus on the present moment without judging these experiences or trying to change them. MBCT has been found to be effective in preventing relapse, and there is some evidence that it may be effective as a treatment of depression as well.²³ MBCT is also being offered as individual rather than group-based therapy however research on the effectiveness of this format is currently limited.

1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington DC: Author.
2. Lacasse, J. R., & Leo, J. (2015). Antidepressants and the chemical imbalance theory of depression. The Behavior Therapist, 38(7).
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4. Flint, J., & Kendler, Kenneth S. (2014). The genetics of major depression. Neuron, 81(3), 484-503. doi: http://dx.doi.org/http://dx.doi.org/10.1016/j.neuron.2014.01.027
5. Lohoff, F. W. (2010). Overview of the genetics of major depressive disorder. Current psychiatry reports, 12(6), 539-546. doi: http://dx.doi.org/10.1007/s11920-010-0150-6
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9. Heim, C., & Binder, E. B. (2012). Current research trends in early life stress and depression: Review of human studies on sensitive periods, gene–environment interactions, and epigenetics. Experimental Neurology, 233(1), 102-111. doi: http://dx.doi.org/http://dx.doi.org/10.1016/j.expneurol.2011.10.032
10. Vanderhasselt, M.-A., & De Raedt, R. (2012). How ruminative thinking styles lead to dysfunctional cognitions: Evidence from a mediation model. Journal of Behavior Therapy and Experimental Psychiatry, 43(3), 910-914. doi: http://dx.doi.org/10.1016/j.jbtep.2011.09.001
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15. Barth, J., Munder, T., Gerger, H., Nuesch, E., Trelle, S., Znoj, H., . . . Cuijpers, P. (2013). Comparative efficacy of seven psychotherapeutic interventions for patients with depression: A network meta-analysis. PLoS Med, 10(5), e1001454. doi: http://dx.doi.org/10.1371/journal.pmed.1001454
16. Beck, J. S. (2011). Cognitive behavior therapy: Basics and beyond (2nd ed.). New York, NY: Guilford Press.
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