context: If you've been diagnosed with clinical depression, you may be having trouble getting to sleep or staying asleep. There's a reason for that. There is a definite link between lack of sleep and depression. In fact, one of the common signs of depression is insomnia or an inability to fall and stay asleep. That's not to say insomnia or other sleep problems are caused only by depression. Insomnia is the most common sleep disorder in the U. S., affecting nearly one out of every three adults at some point in life. More women suffer from insomnia than men, and as people get older, insomnia becomes more prevalent. Most experts agree that adults need seven to nine hours of sleep a night. But even without depression, according to the National Sleep Foundation, the average American only gets about 6.9 hours. When you add depression to the mix, the problems with sleep are compounded. An inability to sleep is one of the key signs of clinical depression. Another sign of clinical depression is sleeping too much or oversleeping. Having a sleep disorder does not in itself cause depression, but lack of sleep does play a role. Lack of sleep caused by another medical illness or by personal problems can make depression worse. An inability to sleep that lasts over a long period of time is also an important clue that someone may be depressed. Clinical depression is a mood disorder. It causes you to feel sad, hopeless, worthless, and helpless. Sure, we all feel sad or blue from time to time. But when you feel sad for long periods and the feelings become intense, the depressed mood and its associated physical symptoms can keep you from living a normal life. Normal sleep is a restorative state. However, when sleep is disrupted or inadequate, it can lead to increased tension, vigilance, and irritability. Physical or emotional trauma and metabolic or other medical problems can trigger sleep disturbances. Poor sleep can lead to fatigue. With fatigue, you exercise less and that leads to a decline in your fitness level. Eventually, you find yourself in a vicious cycle of inactivity and disturbed sleep, which causes both physical and mood-related symptoms. Insomnia is difficulty initiating or maintaining normal sleep. It can result in nonrestorative sleep and interfere with or impair the way you function during the day. Insomnia is often a characteristic of depression and other mental health disorders. With insomnia, you may sleep too little, have difficulty falling asleep, awaken frequently throughout the night, or be unable to get back to sleep. With untreated depression, you may have overwhelming feelings of sadness, hopelessness, worthlessness, or guilt. These feelings can interrupt sleep. Or your mind may be in overdrive, ruminating about situations over which you have no control. With that rumination come high levels of anxiety, fears about poor sleep, low daytime activity levels, and a tendency to misperceive sleep. The treatment for clinical depression depends on how serious the mood disorder is. For instance, psychotherapy (talk therapy or counseling) combined with medications (antidepressants) is highly effective in treating depression. The antidepressants work to decrease symptoms of sadness or hopelessness while the psychotherapy helps improve coping skills and change negative attitudes and beliefs caused by depression. Talk therapy also works on coping skills to help you fall asleep more easily. Your doctor may treat sleep disorders and depression with an antidepressant such as an SSRI -- a selective serotonin reuptake inhibitor. Additionally, your doctor may prescribe a sedating antidepressant or a hypnotic medication -- a sleeping pill or other medication that helps people sleep. Your doctor may prescribe one of the following antidepressants that can also help you sleep: An SSRI such as Zoloft, Prozac, Celexa, Lexapro, and Paxil. SSRIs can be effective for treating depression but may take several weeks or longer to become effective. At the beginning, they may also cause or worsen insomnia, for which your doctor may prescribe a separate sleeping medication on a short-term basis. Other antidepressant medicines that affect serotonin through multiple serotonin receptors include Viibryd and Trintellix. Tricyclic antidepressants (including Pamelor and Elavil) SNRIs (serotonin/norepinephrine reuptake inhibitors such as Effexor, Pristiq, Khedezla, Fetzima, or Cymbalta) Sedating antidepressants (such as Remeron). The antidepressant trazodone is not widely used to treat depression but because it can cause drowsiness it is often paired as a sleep aid that can be used with other antidepressants. Your doctor may prescribe one of the following hypnotics or sleeping pills to help resolve insomnia: Ambien/ Ambien CR Belsomra Lunesta Restoril Sonata Rozerem Here are some lifestyle tips that -- in combination with antidepressants and sedative-hypnotics -- may help improve sleep and resolve insomnia: Meditation, listening to soft music, or reading a book before bedtime can help increase relaxation while focusing your thoughts on neutral or pleasant topics. Clear your head of concerns by writing a list of activities that needs to be completed the next day. Then tell yourself you will think about it tomorrow. Get regular exercise -- but no later than a few hours before bedtime. Daily exercise, including stretching and conditioning exercises, can help to facilitate sleep and relieve the associated anxiety many people have about staying asleep. Avoid looking at a bright screen (for example, a laptop or television) prior to bedtime because the light emitted from computer monitors or LCD screens can suppress release of the natural hormone melatonin, which signals the brain to go to sleep. High levels of arousal associated with racing thoughts, worries, or rumination may delay sleep onset. Relaxation therapies such as yoga and deep abdominal breathing may be useful in initiating sleep. Don't use caffeine, alcohol, or nicotine in the evening. Check the ingredients in any over-the-counter or prescription medications to see if "sleeplessness" is indicated. Some medications such as headache medicines contain caffeine, which can cause poor sleep. Don't lie in bed tossing and turning. Get out of bed and do some light activity (such as reading or listening to soft music) in another room when you can't sleep. Go back to bed when you are feeling drowsy. Use the bed only for sleeping and sex. Don't lie in bed to watch TV or read. This way, your bed becomes a cue for sleeping, not for lying awake. Take a warm shower right before bedtime to increase deep sleep as your body cools. Keep your bedroom at a cool temperature. Wear earplugs and a sleep mask if noise and light bother your sleep. Get blackout shades for your bedroom to keep outside lights from bothering you. A white noise machine may also help if you cannot sleep because of household noises.