Exogenous (does not have origin in body) causes of insomnia are a new set of environmental conditions. These conditions include Noise or loud noise, condition / unfamiliarity of the bed, temperature of the bedroom, any kind of sleep medications. These conditions may soon disappear as soon as your body becomes accustomed to the new set of conditions except medications. In case of medications, our body develops a kind of dependency. That means if you are taking pills or medicines to go to sleep at night, it will be harder for you to go to sleep without taking one.
Loud noise at your neighborhood or a dog barking at your own house can make you restless at night if you are not used to it. If you are sleeping on an uncomfortable bed, it may also cause sleeplessness and insomnia. The bed you are sleeping on must be comfortable and your spine should be at a comfortable position so that your body can go to rest easily. The temperature of your bedroom should not be too hot or too cold. It will be hard for your body to maintain the calm state of mind and body in case you are sleeping in a hot and humid condition.
Insomnia causes also include internal illnesses or problems with the body. These include waiting for sleep, mental disorders like stress, depression and anxiety.
Mental conditions like stress is one of the largest causes of insomnia. An overstressed and exhausted mind can not go to sleep easily. Over thinking about school, work, family and health makes it difficult to go to sleep. Human life is full of various kinds of stressful situations. Death or illness of a loved one, divorce or a job loss can cause a lot of stress.
Medications prescribed for other body ailments can also result in insomnia. Some medicines used for blood pressure, heart or prescribed antidepressants may interfere with your sleep at night. Some pain killers or weight loss products may contain caffeine which is a stimulant.
Bad eating habits like excessive alcohol intake and cigarettes can also cause insomnia. Alcohol is a sedative and it can have a relaxing and calming effect on your brain, but that only occurs when you drink certain doses (one or two). If you go beyond that certain doses, it will have a negative impact on your sleep and will result in frequent awakenings during night. Similarly, cigarettes contain a stimulant substance called nicotine. Many smokers may find smoking relaxing, but it is just psychological. No substance containing a stimulant can help you with sleep. It can only disturb your sleep. Drinking coffee late in the evening is also a big cause of restlessness or insomnia during night. Coffee contains caffeine, a stimulant. Being a stimulant it can cause mental and physiological arousal. Stimulants increases mental and physical alertness therefore it is good if you are going to perform some work that needs high level of mental and physical alertness.