Symptoms   The symptoms of clinical depression can vary from person to person. The symptoms can range from mild to severe and the cause's can often be complex.   If you have been experiencing five (5) or more of the below symptoms for more than two (2) weeks, if suicide is a serious concern, or if the symptoms are severe enough to interfere with a daily routine -- see your doctor or qualified mental health professional. 1.   Persistent sad, anxious or "empty" mood. 2.   Sleeping too much or too little; middle-of-night or early-morning waking 3.   Reduced appetite and weight loss, or increased appetite and weight gain 4.   Loss of pleasure and interest in activities once enjoyed, including sex 5.   Irritability, restlessness 6.   Persistent physical symptoms that do not respond to treatment (such as chronic pain or digestive disorders) 7.   Difficulty concentrating, remembering or making decisions 8.   Fatigue or loss of energy 9.   Feeling guilty, hopeless or worthless 10. Thoughts of death or suicide