According to the Centers for Disease Control and Prevention, depression affects one in 10 Americans. Depression can be rooted in a variety of causes, including chemical imbalances; life events, such as death, job loss or abuse; and seasonal issues, such as certain holidays or anniversaries or the reduction of daylight in fall and winter. Though depression can be linked to genetics, many people without a family history experience it as well.

The National Institute of Mental Health identifies the following as possible signs of depression:

• Persistent sad, anxious or “empty” mood
• Feelings of hopelessness or pessimism
• Feelings of guilt, worthlessness or helplessness
• Loss of interest or pleasure in hobbies and activities that was once enjoyable, including sex
• Decreased energy, fatigue; feeling “slowed down”
• Difficulty concentrating, remembering or making decisions 
• Trouble sleeping, early morning awakening or oversleeping
• Changes in appetite and/or weight
• Thoughts of death or suicide, or suicide attempts
• Restlessness or irritability
• Persistent physical symptoms, such as headaches, digestive disorders and chronic pain that do not respond to routine treatment.

Not everyone who is depressed exhibits these symptoms, while some people may experience several.

Men, for instance, often experience depression differently than women, and may cope differently with the symptoms, according to NIMH. Men appear to be more willing to acknowledge fatigue, irritability, loss of interest in work or hobbies and sleep disturbances, but may be reluctant to admit feelings of sadness, worthlessness and excessive guilt. In fact, more than four times as many men as women die by suicide in the United States, though women make more suicide attempts during their lives.

According to NIMH, substance use can mask depression, making it more challenging to identify as a separate illness that needs treatment.

When seeking a diagnosis or treatment for depression, make sure to check references, insurance and licensing of the mental health professional.