Relationship problems, financial trouble, unemployment and grief are few of the more well-known triggers of depression. But do you suffer from depression even though the aforementioned causes do not apply to you?
That's because there are lesser-known causes that could result in depression. Ask yourself whether you have these 12 lesser-known causes of depression:
The more common type of Seasonal affective disorder (SAD) is associated with the winter season.
But did you know this form of depression strikes in the summer, when the weather is warm.
Health.com quoted Dr. Alfred Lewy, professor of psychiatry at Oregon Health and Science University as saying that this warm weather depression arises when the body experiences a delay when adjusting to new season.
The delay in adjustment could be due to imbalances in brain chemistry and the hormone melatonin.
Too many choices
Having too much variety - whether it's types vitamins, shampoo or even breakfast cereal can actually be overwhelming for some.
While some shoppers can identify items that will meet their needs, others respond to choice overload by exhaustively reviewing the options to get the very best item.
Research suggests that this coping style is linked to perfectionism and depression.
Lack of fish in the diet
Low intake of omega-3 fatty acids, found in salmon and vegetable oils, may be associated with a greater risk of depression.
A 2004 Finnish study found an association between eating less fish and depression in women, but not in men.
These fatty acids regulate neurotransmitters like serotonin, which could explain the link. Fish oil supplements may work too - at least one study found that they helped depression in people with bipolar disorder.
Where you live
Research has found that people living in the city have a 39 per cent higher risk of mood disorders than those in rural regions.
According to a study done earlier this year, people living in the city have more activity in the part of the brain that regulates stress - and higher levels of stress could lead to psychotic disorders.
Nicotine affects neurotransmitter activity in the brain which results in high levels of dopamin and serotonin (which is also the mechanism of action for antidepressant drugs).
This could be the reason why nicotine is addictive. It also explains why mood swings come with withdrawal, as well as why depression is associated with smoking cessation.
Avoiding cigarettes - and staying smoke free - could help balance your brain chemicals.
Poor sleep habits
Not only does sleep deprivation make you irritable, it can also increase the risk of depression.
Dr Matthew Edlund, Director of the Centre for Circadian Medicine gave a pretty straight forward explanation, "If you dont sleep, you do not have time to replenish your brain cells and the brain stops functioning well."
This may be one of the many factors that could lead to depression.
Spending too much time on social networking sites could also be associated with depression, especially in teens and pre-teens.
Studies showed that Internet addicts struggle with real-life human interaction and lack of companionship. Some experts have dubbed this type of depression as "Facebook depression".
End of a TV show or movie
The end of something important, like a favourite TV show, movie, or a big home renovation, can trigger depression in some people.
For example, Avatar fans reported feeling depressed and even suicidal because the movie's fictional world wasn't real. There were similar reactions to the final installments of the Harry Potter movies.
According to experts, this happens when people watch primarily for companionship. With regards to the Avatar example, experts suspect that people were so involved that they forgot about their real lives and problems.
Depression can occur when the thyroid, a gland in the neck, doesn't produce enough hormones.
This is known as hypothyroidism and the lack of such neurotransmitters deregulates serotonin levels.
If you experience depression, together with cold sensitivity, constipation or fatigue, go for a thyroid test and take the relevant medicine.
Poor sibling relationships
Unhappy relations with siblings before the age of 20 can lead to depression later in life, according to a 2007 study in the American Journal of Psychiatry.
Research suggests that proper sibling relationships can help children develop socialisation skills. Regardless, too much squabbling is associated with a greater risk of developing depression.
Birth control pills
Some women taking birth control pills may experience depression due to the presence of a synthetic version of progesterone in the pills.
According to Dr. Hilda Hutcherson, clinical professor of obstetrics and gynecology at New York's Columbia University, women with a history of depression or prone to depression have an increased chance of experiencing depression while taking birth control pills.
However, it does not happen to every woman taking oral contraceptives.
Medications can also cause depression.
For example, drugs prescribed to clear up severe acne may cause depression or suicidal thoughts. Anxiety and insomnia drugs such as Valium or Xanax may also cause depression.
Other drugs that may cause depression include those prescribed to treat high blood pressure and cholesterol-lowering drugs such as Lipitor.
It is best to read the potential side effects when you take a new medication and check with the doctor whether you are at risk.