Not all unhappiness is depression. .
Depressed mood, low energy, and loss of interest or pleasure are core features of depression. Low concentration, low self-esteem, feelings of guilt, pessimism, thoughts of self-harm or suicide, disruption in sleep patterns, changes in appetite and decreased sexual desire are other common symptoms. Social and occupational functioning is impaired. Several of these symptoms must last for at least two weeks for a diagnosis of depression to be made. Each episode of depression can be of different severity. The number, type, and intensity of symptoms determine the severity of depression; divided into three groups as mild, moderate and severe.
The subtypes of depression are defined as follows. Chronic major depression is considered when several of the above-mentioned symptoms are fully present for 2 years or more. The pattern of regular onset and improvement of depressive symptoms in a particular season is called seasonal affective disorder. If a depressive episode starts within 4 weeks after birth, it is called post partum depression. If psychotic symptoms in the form of hallucinations and delusions are observed in a depression attack, it is called depression with psychotic features. Reactive mood is called excessive sleeping, overeating, rejection sensitivity in interpersonal relationships, and atypical depression. The subtype, which is characterized by symptoms such as non-reactive mood, lack of pleasure, weight loss, guilt, slowing down in movements and intense affect, mood worsening in the morning, waking up very early in the morning and not being able to sleep again, is called melancholic depression.
Depression is more common in women. 2 out of 10 women and 1 out of 10 men suffer from depression. Depression is seen in 1 out of every 10 people who apply to the hospital. Depression can begin at any time in life, from six months of age to the end of life.