Depression is a mood disorder that causes a persistent feeling of sadness and loss of interest and things that would usually be fun or needful in happiness. Bipolar depression (The most common type) is when you constantly get waves or spikes of fully extreme sadness, but other times you may be very happy.
su!cidal behavior can be many things, su!cidal behavior can be talking about su!cide— for example, making statements such as "I wish I were not living" or "I wish I hadn't been born", being preoccupied with death, dying or violence, feeling trapped or hopeless about a situation, or doing risky or self-destructive things, such as using dr_gs or driving recklessly.