Clinical depression - Causes 


Photo of someone who has been drinking

Depression can be triggered by more than one factor 

There is no single cause of depression. You can develop it for different reasons and it has many different triggers.

For some, an upsetting or stressful life event  such as bereavement, divorce, illness, redundancy and job or money worries  can be the cause.

Often, different causes combine to trigger depression. For example, you may feel low after an illness and then experience a traumatic event, such as bereavement, which brings on depression.

People often talk about a "downward spiral" of events that leads to depression. For example, if your relationship with your partner breaks down, you're likely to feel low, so you stop seeing friends and family and you may start drinking more. All of this can make you feel even worse and trigger depression.

Some studies have also suggested you're more likely to get depression as you get older, and that it's more common if you live in difficult social and economic circumstances.

Stressful events

Most people take time to come to terms with stressful events, such as bereavement or a relationship breakdown. When these stressful events happen, you have a higher risk of becoming depressed if you stop seeing your friends and family and you try to deal with your problems on your own.


You may have a higher risk of depression if you have a longstanding or life-threatening illness, such as coronary heart disease or cancer.

Head injuries are also an often under-recognised cause of depression. A severe head injury can trigger mood swings and emotional problems.

Some people may have an underactive thyroid (hypothyroidism) resulting from problems with their immune system. In rarer cases a minor head injury can damage the pituitary gland, a pea-sized gland at the base of your brain that produces thyroid-stimulating hormones.

This can cause a number of symptoms, such as extreme tiredness and a loss of interest in sex (loss of libido), which can in turn lead to depression. 


You may be more vulnerable to depression if you have certain personality traits, such as low self-esteem or being overly self-critical. This may be because of the genes you've inherited from your parents, or because of your early life experiences. 

Family history

If someone else in your family has suffered from depression in the past, such as a parent or sister or brother, then it's more likely you will too.

Giving birth

Some women are particularly vulnerable to depression after pregnancy. The hormonal and physical changes, as well as added responsibility of a new life, can lead to postnatal depression.


Becoming cut off from your family and friends can increase your risk of depression.

Alcohol and drugs

Some people try to cope when life is getting them down by drinking too much alcohol or taking drugs. This can result in a spiral of depression. 

Cannabis helps you relax, but there is evidence that it can bring on depression, especially in teenagers.

And don't be tempted to drown your sorrows with a drink. Alcohol is categorised as a "strong depressant" and actually makes depression worse. 

Page last reviewed: 19/08/2014

Next review due: 19/08/2016


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The 12 comments posted are personal views. Any information they give has not been checked and may not be accurate.

HF203 said on 03 September 2014

I have been feeling low for months now. All the things that used to make me happy just do not any more. I just can not be bothered with life or people. i put a good show on and people at work think I am always bubbly and happy. I have a nice family and live in a good area and have a nice house. I am nearly 50 and i Just feel life has passed me over. Things that should be making me happy just makeme feel low andI feel un motivated. I feel have wasted my life on my husbands dreams and family and now I am left with nothing. I feel oftern the family see me as a bit of a joke tubby old boring Mum. I am over weight but can not motavate myself i have joined a gym and try to go swimming twice a week but hate taking my clothes off infront of all the beautifull people. I used to be such a happy person with dreams of my own I can't bring myself to even think of them now as it makes me cry asI know I will never be free of this darkness. I feel this time on earth has not been my turn. I have always worked hard and put others first what has gone wrong with me?

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RomildaVane said on 29 December 2013

I am 21 years old and since the age of 15 I have felt as though I have needed some kind of help and support with depression. At the age of 16 I began to self harm, my mum found out and I got into terrible trouble, at the age of 17 I had turned to alcohol and drugs and taking control of my eating habits. I finally decided to get some help. I plucked up the courage to make an appointment with my GP. I walked into the office and was asked what I was here to talk about, when I explained how I ha been feeling my dr told me it was because of my age without really attempting to get to the bottom of things. I felt ridiculed and of course turned back to alcohol and drugs and then began to have unsafe sex with numerous people in order to feel some form of closeness with somebody, anybody. At the age of 19 I fell pregnant however due to my severe drug use I did not notice the absence of my menstrual cycle and found out at 23 weeks. I was told it was too late to have an abortion so I decided to put the child up for adoption, this still stands to be the hardest thing I have ever done, despite what I have been through with being bullied from the age of 14-18 and all the problems I have had within my family dynamics. It was during my pregnancy that I pushed everyone away and left myself with only one person. My parents tried to kick me out of the house, more than happy to leave a 7 month pregnant teenager out on the streets as to protect their reputations from having a pregnant teen for a daughter. I finally pulled through and I have to admit in the beginning the adoption process was excellent, very supportive and respectful however once I had signed all parental responsibility over to the adoption team they didn't seem to care. (Cont…)

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Goingoutofmymind said on 08 December 2012

I sleep and wake up around 10 am and wake up with a angry feeling I am so jumpy and feel like I cannot operate properly or even talk in a full sentence without slurring or stuttering and when getting a taxi to work I have this feeling of just opening the door and jumping out but I know it's stupid and have a loving family I feel like I am losing my mind and have lost myself I don't know me know me anymore , I have had this feeling all my life when I was younger I always felt advanced beyond my years know at the age of 26 I feel useless and no good I have tried antidepressants but they make me feel worse I cannot go to work on them as I feel uneasy and my heart starts beating fast and I keep yawning every 2 minutes ,back in school I was a loner was always angry at the world and did not care , I feel like I need help but I don't want anybody to find out about how I am feeling , I don't hardly talk to anyone only if I have to and always thinking of ways to make myself look better , am I depressed and if so what shall I do ?

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Casualty said on 26 January 2012

My depression brought on by prescribed sleeping tablets, Benzodiazepines. It triggered psychosis or rewired the brain causing constant permanent severe head pain. The GP made it worse. More benzodiazipines were prescribed, then antidepressants - the side effects were horrific & told that this was the illness getting worse!!
Doctors do not listen & just jump in & prescribe.
The are never responsible & just state they've learnt something but won't stop.
Be careful you just may end up in a horrid chemical soup, that's worse than the induced pain or depression.

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Cedders said on 18 October 2010

The genetics of depression also reminds me of an interesting article in the Guardian this week by Ben Goldacre

It seems that thinking of mental health conditions as genetically caused or biologically distinct increases the stigma and discrimination associated with condition.

Not that that has any bearing on whether there actually is a genetic component to unipolar depression, but the review does match my experience.

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Cedders said on 18 October 2010

Seems more helpful and balanced since the review of 09/09/2010. However, the "Research shows that some genes increase the risk of depression after a stressful life event" still sounds like it's based on the same 5-HTTLPR findings that weren't generally reproduced. (In other words, there might be such genes but I don't think the articles right in suggesting they have already been discovered.)

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Cedders said on 15 July 2010

I wonder if this page could say more about social causes of depression. Compared to the section on genetics, there's not much, but the evidence as I understand it is much stronger, for example linking depression to lack of a confiding partner or early bereavement. One of the the most well-known publications here is Brown and Harris's _Social Origins of Depression_ (1978).

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Cedders said on 15 July 2010

There are medical conditions that can contribute to depression as this page says. There are a few others (although of course, people with depression are often assumed to suffer from hypochondria, so maybe that's why these aren't included!). There are various possible hormonal causes, including a lot of research into cortisol. Dietary deficiencies, eg folic acid, B6, B12, are also sometimes mentioned. This is *not* to say anything one way or another about supplements or a healthy diet, merely that they are known possible causes. There's a handy list in _Mental Health Issues in Primary Care_ by Elizabeth Armstrong.

This isn't intended as advice.

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Cedders said on 15 July 2010

On the psychological side,I suggested the information about interaction between cognitive style and life events is very strong, and so could be mentioned. Cognitive style is things like whether or not negative events are seen as permanent (stable), one's own fault (internal) and wide-ranging (global). I don't have references for this to hand, but it's in standard psychology textbooks. Work on rumination is continuing.

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Cedders said on 15 July 2010

The hypotheses involving neurotransmitters are not supported by consistent evidence; they are merely hypotheses to explain how antidepressants may work.

Reserpine has an anti-serotonergic effect, and yet was the first chemical to show an anti-depressive effect in a randomised controlled trial (More information in David Healy's _The Antidepressant Era_) That's not to say that antidepressants may not work through other mechanisms.

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Cedders said on 15 July 2010

The information about the 5HTT gene is outdated. See "Interaction Between the Serotonin Transporter Gene (5-HTTLPR), Stressful Life Events, and Risk of Depression: A Meta-analysis", Risch et al. JAMA 2009;301:2462-2471.

Results: "the number of stressful life events was significantly associated with depression (OR, 1.41; 95% CI,1.25-1.57). No association was found between 5-HTTLPR genotype and depression in any of the individual studies nor in the weighted average (OR, 1.05; 95% CI, 0.98-1.13) and no interaction effect between genotype and stressful life events on depression was observed (OR, 1.01; 95% CI, 0.94-1.10 "

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Cedders said on 15 July 2010

I added a comment here on the content back in February, questioning some of the statements and also perhaps suggesting a slightly different emphasis. I asked for the content to be reviewed on 20 April, and had a proper reply on 28 May (ref: 47082ab) saying the citations I gave would be followed up, an expert clinician would review the topic before it is republished. However, I think this has still to happen, and on 12 July, my comment was removed saying "We cannot allow messages offering medical advice.... Please consider re-submitting your message without offering any 'advice' to other users."

So far as I can see, there was no medical advice in my comment. As I made it clear, I'm not medically qualified, but the information I mentioned was all from respectable sources and only vaguely touched on diagnosis and treatment. So I will re-submit in smaller pieces so I can find out which section is objectionable.

I do think it would help if more of the statements on this site were referenced.

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