Symptoms of a depressive disorder include at least five of the following changes in the individual’s previous characteristics: loss of motivation and inability to feel pleasure; deep chronic sadness or distress; changes in sleep patterns; lack of physical energy (apathy); feelings of hopelessness and worthlessness; difficulty with concentration; overeating or loss of appetite; withdrawal from interpersonal interactions or avoidance of others; death wishes, or belief in his/her own premature death. In children, the first signs of depression may be irritation and loss of concentration, apathy and distractibility during classes, and social withdrawal. Some adults initially complain of constant fatigue, even after long hours of sleep, digestive disorders, headaches, anxiety, recurrent memory lapses, and insomnia or excessive sleeping. An episode of major depression may be preceded by a period of dysthymia, a mild but persistent low mood state, usually accompanied by diminished drive, decreased affective response, and loss of interest in normal social activities and hobbies. Most individuals with depression have difficulty in dealing with the challenges of daily life, and even minor obstacles or difficulties may trigger exaggerated emotional responses. Frustrating situations are frequently met with feelings of despair, dejection, resentment, and worthlessness, with people easily deviating from their goals. People with depression may try to avoid social situations and interpersonal interactions. Some people with depression overeat, while others show a sharp loss of appetite (anorexia). In some individuals, medical treatments for some other existing illness may also cause depression as an adverse reaction. For instance, antihypertensive drugs, steroids, muscle relaxants, anticancer drugs, and opioids, as well as extensive surgery such as a coronary bypass may lead to depression. Cancer and other degenerative diseases, chronic painful conditions, metabolic diseases or hormonal changes during adolescence or after childbirth, menopause or old age may be potential triggers for depression. When the first onset of depression occurs after the age of 60, there is a greater possibility that the causative factor is cerebrovascular (blood vessels in the brain) degeneration.