Depression is one of the most common mental disorders. Main feature is the depressed mood. In other words, the sufferer feels sorrow, sadness, melancholy, misery for a long period of time. At the same time, the sufferer loses interest and draws no pleasure from almost all activities, becomes socially withdrawn, has no energy, gets tired easily and has difficulty concentrating. Sleep, appetite and the libido are often disturbed.
Bipolar disorder is characterised by the alternation of depressive episodes to manic episodes. We would not exaggerate if we said that mania is the opposite of depression. A person who is in mania has a persistently elevated, euphoric or irritable mood, inflated self-esteem or grandiosity, decreased need for sleep, increased talkativeness, increased activity level and excessive involvement in pleasurable activities.