A depressed mood is a normal reaction to life's struggles, but when depression becomes intense and lasts for long periods of time, it can prevent someone from leading a normal life.
Experts say signs of depression include feeling subjectively sad, not being able to enjoy yourself anymore, and feeling worthless, helpless, and hopeless.
In the worst cases that includes losing interest in sex and relationships, withdrawing from people, and suicidal thoughts.
Experts say many times it's someone else who will notice a change in behavior, not the person who's depressed.
If you have any of the symptoms for most of the day or nearly every day for two weeks or more, you should talk to your doctor.
There are a list of treatment options for depression including psychotherapy and medications.
Doctors say the key is to not be afraid to ask for help.
"As a practical matter, when people come into psychotherapy, when they come for help, they generally say they've never felt safer or in a better spot. So, if I can be encouraging in a particular way it's that it's scary in thinking as a practical matter when you're actually in a psychotherapeutic situation, it can feel awfully good," said Scott Bea, Psy.D. of Cleveland Clinic.
Dr. Bea says many times, a combination of psychotherapy and medication work best as a treatment option.