Depression is a mood disorder① that causes you to feel sad or hopeless for an extended period of time. More than just a bout of the blues or temporary feelings of grief or low energy， depression can have a significant impact② on your enjoyment of life， your work， your health， and the people you care about.
Depression affects people differently. Some feel down for extended periods of time； for others the feelings of depression come and go. If you have short episodes③ of mild depression， you may be able to continue to work and take care of daily activities.
However， if you do not seek some form of treatment for your depression， you are at risk for getting more depressed or becoming physically ill. In severe cases， depression can cause people to become incapable of communicating， unable to do routine activities， or suicidal. In these cases， it is essential to seek medical attention.
People with depression may be reluctant to seek help because they feel that it is a sign of personal weakness or a character flaw or that they should be able to pull out of it on their own.
We now know that depression， like other medical conditions， has a chemical and biological basis. Treatment for depression is safe and usually effective even for severely depressed people.
Depression may be triggered④ by stressful life events， other illnesses， certain drugs or medications， or inherited traits. Although causes of depression are not entirely understood， we know it is linked to an imbalance⑤ in brain chemistry. Once the imbalance is corrected， symptoms⑥ of depression generally improve.
Depression is more than just the normal， temporary⑦ feelings of sadness and hopelessness associated with difficult life events. Common symptoms include：
Depressed mood； Inability to enjoy activities； Problems concentrating； Poor memory； Difficulty making decisions； Changes in eating habits； Weight gain or weight loss； Changes in sleeping habits； Difficulty going to work or taking care of your daily responsibilities； Feelings of guilt and hopelessness； wondering if life is worth living (common)； Slowed thoughts and speech； Preoccupation⑧ with thoughts of death or suicide； Complaints that have no physical cause (somatic complaints) such as headache and stomachache.
All of these symptoms can interfere⑨ with your quality of life. Even if you don’t have major depression， if you have experienced a few of these symptoms for at least 2 weeks you may have a less severe⑩ form of depression that still requires treatment.
① disordern. 混乱，无秩序； 紊乱，失调；不适，小病
② impactvt. 对……产生影响 n. 冲击，撞击，碰撞
③ episoden. (整个事情中的)一个事件；(文艺作品中的)插曲
④ triggervt. 触发，引起； 扣扳机开(枪)；发射 n. 能引起反应的刺激物
⑤ imbalancen.不均衡状态；不安定
⑥ symptomn.症状；征兆，表征
⑦ temporaryanj.临时的；暂时的 n.临时工，临时事物
⑧ preoccupationn. 全神贯注，入神；抢先占据；抢先占有
⑨ interferevi. 妨碍；冲突；抵触；介入；干涉，干预
⑩ severeadj.严重的；剧烈的；严厉的；苟刻的
抑郁症
抑郁是在一段时间内持续的一种精神絮乱，它让人感觉悲伤，对生活失去希望。不止发作一次的悲伤心情，或没有精力，抑郁对人们的生活，工作，健康，甚至对周围的人们都会产生很大的影响。
抑郁对人们的影响是不同的。有些人经常情绪失落，而有些人只是偶尔有这种情绪。如果你偶尔有这轻微的抑郁，可能你能继续工作，应付日常工作。
然而，如果不对你的抑郁寻求一些治疗，你可能就会变得更加抑郁，或增加生病的风险。严重抑郁会导致人无法正常交流，不能进行日常的活动，甚至自杀。在这种情况下，寻求药物治疗就非常重要。
患抑郁的人通常认为它是个人性格上的弱点，或是性格上的缺陷，他们认为能够通过自身的努力消除，从而他们不愿意寻求帮助。
我们知道，抑郁和其它的疾病一样，都有生物和化学基础。治疗是安全的，对于患有严重抑郁的人，它通常是非常有效的。
过高压力的生活事件，其它疾病，一些药物或治疗，或遗传因素等都有可能引发抑郁。虽然抑郁的起因不能完全搞清楚，但我们知道它和大脑内某种化学物质的失衡有联系。一旦这种失衡被纠正之后，抑郁就会大大的改善。
抑郁是一种和困难生活事件相关的，自然的，临时性的，伤心，失望的一种感受。一般的症状包括：
情绪抑郁；不能享受运动；注意力无法集中；记忆力差；优柔寡断；饮食习惯改变；体重增加或减少；睡眠习惯改变；无法正常地进行日常工作和生活；有罪恶感，感觉没有希望；怀疑生命存在的价值（普遍现象）；思考缓慢，表达缓慢；常常想到死亡，或自杀；抱怨不存在的身体病痛，例如，头痛，胃痛。
所有的这些病症都会影响生活质量。即使没有这些主要的症状，如有这其中这些部分现象持续超过二周时间的，可能就患有轻度的抑郁，仍然需要治疗。