Depression is a common mental illness. Patients may feel sad, guilty, worthless, hopeless, or want to commit suicide, or harm themselves.

1. What Is Depression?

Depression is a common but severe mood disorder. Its symptoms are low mood, slow thinking, decreased speech and movements, decreased interest, pessimism, lack of initiative, self-blame, poor diet, and long-time sleep. Further, patients may worry about developing other diseases, feel uncomfortable in their bodies, and may even commit suicide. It causes severe symptoms that affect the way you feel, think, and process daily activities, such as sleeping, eating, or working. To be diagnosed with depression, symptoms must be present for at least two weeks. Depression severely affects the lives and works of patients and brings a heavy burden to families and society.

The most prominent symptoms of depression are usually a sad or irritable mood and/or loss of interest in all or most activities that used to be pleasurable. Patients may also experience guilt despite having done nothing wrong, as well as feeling worthless, hopeless, and/or have recurring thoughts of wanting to die, kill, or otherwise harm themselves, as in cutting or burning themselves.【1】


2. How common is depression?

Depression is one of the most common forms and symptoms of mental illness in the United States, with around five percent of adults suffering from depression as of 2019. Features of depression are long-term feelings of sadness and hopelessness, and it can affect one’s sleeping and eating habits, social and work life, and daily activities. Symptoms of depression include a loss of interest in things they love, loss of energy, feelings of worthlessness and guilt, anxiety, and thoughts of death or suicide.

Depression, and mental health in general, were recently brought to the forefront during the COVID-19 pandemic. During this period, normal life is severely disrupted and people are living in panic. Symptoms of depression are present among a large number of the U.S. population.

Depression in the United States is more common among women than men, with around 3.5 percent of men suffering from depression compared to just under six percent of women. The most common age at which adults experienced a major depressive episode as of 2020 was between 21 and 25 years for both sexes, with 11.4 percent of men and 23.2 percent of women between these ages reporting such an episode in the past year. Depression is also common among youth, with up to 25 percent of teenage females and 9 percent of males experiencing a major depressive episode in the past year as of 2020.

Depression is a leading cause or risk factor for suicide, highlighting the importance of diagnosis and treatment. This is clear in the fact that in 2018 around 75 percent of suicide victims in the U.S. suffered from depression. As of 2020, around 34 percent of adults with a major depressive episode had serious thoughts of suicide in the past year, while 11 percent made suicide plans, and 3.6 percent attempted suicide.【2】

3. Depression and anxiety

The pathogenesis of bipolar disorder is a manic state, with episodes of mania and high mood in the middle, and at least one depressive episode in the later period. That is called bipolar disorder. However, if there is no mania and lasting depression during the entire process and cycle, that is called depression. Depression alone is relatively rare, and it often goes with bipolar disorder. A simple depression may develop into bipolar disorder as time goes by.

The difference between bipolar disorder and depression is that bipolar disorder has two extremes of emotions, and depression has only one extreme. If the depression does not have a manic emotional state, we can call it simple depression. Because it only has one extreme emotion. That is their difference.

In depression, there may be no mania. Generally speaking, the prognosis of simple depression may be better than that of bipolar disorder. Because mania and depression appear at the same time, it is difficult to stabilize one’s mood within the normal range. So, the patient’s situation will become more complex. If the situation is not controlled in time, it may be more likely to reappear. In this way, there will be more risks, and the prognosis will be worse.【3】

4. Depression symptoms

  • Behavioral symptoms of depression

Loss of interest.

People with depression lose interest in everything. Patients may lose their enthusiasm for life and work and have no interest in anything. They don’t like to communicate with people, relatives, and friends, and don’t like to do things that they were very interested in before.

Low self-evaluation.

People with depression are extremely unconfident, view everything with a negative attitude, think it is worthless, and often devalue their abilities. They may hold a negative attitude towards their present, past, and future, and suffer from strong self-blame, guilt, and a sense of uselessness all the time.

Sexual dysfunction.

Decreased sexual desire can occur early in this disease. Impotence may occur in males and frigidity may occur in females.

Reduced exercises.

The patient’s active exercise during a depressive episode is a prominent and lasting will. Since they lose the enthusiasm for life, they tend to sit alone, and do nothing.


Patients with severe depression will often think about suicide or hurting themselves because they always blame themselves and feel helpful to change the present situation.

  • Physical symptoms of depression

Low mood.

The main physical symptoms are prominent and lasting low mood, depression and pessimism, and no sense of pleasure. Low self-evaluation often results in a sense of uselessness, hopelessness, helplessness, and worthlessness.

Slow thinking.

The patient’s thinking speed is slow and the reaction is slow. He may speak less in a low voice and at a low speed. It is difficult for him to solve problems, and his work and learning abilities will also decrease.


Anxiety is a quite common symptom. It mainly includes nervousness, fear, restlessness, and irritability.

Sleep disorder.

The characteristic sleep disorder of depression is early awakening. That is the change in the continuity of sleep. After waking, people can hardly fall asleep, even though it is early in the midnight or morning.

Decreased appetite.

Patients may lose their appetite, and they can’t feel hunger. For them, eating is only to finish tasks, live, and keep the body functioning. They are not happy when eating delicious food.

Depression causes

Depression is a clinical syndrome associated with genetic, social, psychological, environmental, and biochemical factors, and its causes and pathogenesis are still unclear. Researchers have noticed some factors associated with depression, including:

  • Genetics. Scientists are working on certain genes that might make you more likely to get them. But even if you have them, you probably won’t be depressed. 【4】 Depression can spread in families, but that doesn’t mean you will get depressed just because one of your relatives has depression.
  • Life Events. Bad things that happen to you can lead to depression. This could be the loss of someone close to you, a difficult relationship, or a stressful situation. Other things like your financial situation, your residence, and your marriage may also be influential.
  • Childhood problems. People with uneasy childhood experiences are more likely to suffer from depression. It may come from brain changes caused by trauma at a young age.
  • Other conditions. Drug or alcohol abuse, illness, chronic pain, anxiety, sleep problems, and ADHD may also have a connection with depression.

But please remember, your depression doesn’t necessarily have a “cause”. Sometimes it happens for no reason.


5. Risk factors

Depression is one of the most common mental disorders in the U.S. Current research suggests that depression is caused by a combination of genetic, biological, environmental, and psychological factors.【5】

  • Physiological factors

Biochemical imbalance. Chemicals in the body are out of balance, especially those that can cause abnormal neurotransmission function, such as hormones in the body.

Physical illness. Physical diseases can cause depression symptoms, such as Alzheimer’s, cancer, diabetes, heart disease, etc.

Genetic factors. Studies on family, twins, foster children, etc. show that genetics is an important reason for depression.

Substance abuse. The abuse of some substances (e.g., alcohol, drugs) can lead to depression.

Nutritional deficiencies. Deficiencies of some nutrients (such as folic acid and VIII) can lead to depression.

Medical treatment. Ingestion of some medications, such as sleeping pills, blood pressure pills, birth control pills, etc., may increase symptoms in people with depression.

Obesity. Obese people tend to be more concerned about their weights. Obesity is one of the important reasons for depression.

  • Psychological factors

Personality characteristics. Some people who have low self-confidence, are anxious and overly worried, are extremely sensitive, and worry about being abandoned are prone to depression.

Unreasonable knowledge. People with depression believe themselves incompetent and always blame themselves.

Pressure. Long-term psychological and physical stress can also lead to depression.

  • Social environmental factors

Loss of a loved one, divorce, loneliness, financial situation; laid-off, bankruptcy, stressful work, retirement; going abroad, immigration, etc.

6. What are the types?

  • Major depressive disorder (MDD). It refers to a severe episode of depression. It will severely affect the patient’s social situation. People are unable to work, live and study normally. This kind of depression usually requires immediate hospitalization.
  • Melancholia. Major depressive disorder (MDD) with melancholic features is also called melancholic depression. It is a particular type of MDD that presents with unique characteristics. 【6】
  • Dysthymia. It is a chronic mood disorder that falls under the category of clinical depression. The duration is longer than that of severe depression, but the symptoms are relatively mild.
  • Antenatal and postnatal depression. Clinically, both antenatal and postnatal depression are perinatal depressive disorders, and they only occur at different times. Antenatal depression is more about some anxiety, a sense of loss of one’s ability, and a feeling of fatigue of energy. On the other hand, postnatal depression is more about worrying about the fetus.
  • Cyclothymic disorder. The disorder is a milder form of bipolar type II disorder with mood changing between happiness and depression.
  • Bipolar depression. Bipolar depression is also known as bipolar disorder, and it is a common psychiatric disorder that has both a manic episode and a depressive episode. Furthermore, the first onset may occur at any age.
  • Persistent depressive disorder. It is a psychological disorder with lasting depression.
  • Premenstrual dysphoric disorder. It is an anxiety disorder in pregnant-age women about a week before menstruation.
  • Psychotic depression. It refers to major depressive disorder with psychotic characteristics.
  • Seasonal affective disorder. It is a mood disorder associated with specific seasons, especially winter.

7. Depression Diagnosis

Your doctor will evaluate your symptoms, including how long you have had this disease, when they started, and how they were treated. They’ll ask about the way you feel, including whether you have any symptoms of depression such as:

  • Sadness or depressed mood most of the day or almost every day
  • Loss of enjoyment in once plea
  • Major change in weight (gain or loss of more than 5% of weight within a month) or appetite
  • Insomnia or excessive sleep almost every day
  • Physical restlessness or a sense of being run-down that others can notice
  • Fatigue or loss of energy almost every day
  • Feelings of hopelessness or worthlessness or excessive guilt almost every day
  • Problems with concentration or making decisions almost every day

Recurring thoughts of death or suicide, a suicide plan, or suicide attempt【7】

8. Treatment

  • Medications.

It refers to medicines that treat depression. They may help improve the way your brain uses certain chemicals that control mood or stress. You may need to try several different medicines before finding the one that improves your symptoms and has manageable side effects. A medication that has helped you or a close family member in the past will often be considered. 【8】

  • Psychotherapy.

Commonly used psychotherapeutic methods include supportive psychotherapy, cognitive behavioral therapy, interpersonal therapy, marriage and family therapy, psychodynamic therapy, and other treatments.

  • Light therapy.

Light therapy is a method of using artificial or natural light sources to prevent and treat diseases, mainly for the treatment of seasonal depression. It has a better effect on atypical manifestations of depression such as bulimia and excessive sleep. Light therapy can lead to an advanced circadian rhythm of one’s biological clock, thus inhibiting depression.

  • Electroconvulsive Therapy (ECT)

There is a clinical indication for electroconvulsive therapy. For example, for patients with refractory depression who refuse to eat, want to injure themselves or commit suicide, are allergic to drug therapy, or patients who don’t respond to drugs, electroconvulsive therapy can be taken. It is not simply electric shock therapy. It has medical evidence for improving patients’ symptoms. After about eight to ten times of electroconvulsive therapy, the patient has a significant improvement. However, it also has some mild adverse reactions, like short-term memory loss and physical discomfort.

9. Beyond Treatment: Lifestyle and home remedies

  • Try to be active and exercise.
  • Set realistic goals for yourself.
  • Try to spend time with other people and confide in a trusted friend or relative.
  • Try not to isolate yourself, and let others help you.
  • Expect your mood to improve gradually, not immediately.
  • Postpone important decisions, such as getting married or divorced, or changing jobs until you feel better. Discuss decisions with others who know you well and have a more objective view of your situation.

Continue to educate yourself about depression.【9】

10. Can depression be prevented?

Depression is preventable. Prevention can start from several aspects: improving physical fitness, early treatment, consolidation, preventing recurrence, and so on.

First of all, depressed people may avoid communicating with people. To prevent depression, you must first maintain basic communication and social relations, often communicate with family and friends, and do things that you are interested in.

Secondly, adjust your diet. A good eating habit is the best way to adjust our bodies.

Third, you can improve your mood through exercise. Because moderate exercise every day can promote the secretion of hormones such as adrenaline in our body. This hormone can effectively improve your depressive state.

Fourth, treat everything that happens in life reasonably. Don’t blame yourself for any problems that arise. Even if you have symptoms of depression, you should be clear that this is a disease. It is the same as a cold and fever, and it is not a disease you want to confront. It is just because you are temporarily unable to resist all this.

Therefore, actively seeking help from doctors is beneficial to your health. You can also live a better life later.

11. How can I help people with depression?

  • Accept the reality.

We should accept the reality that he has depression and the fact that he is ill. It is the main premise of our actions. If we cannot accept the reality, we can’t help him at all, because “not accepting” is “harm”.

  • Allow him to suffer.

When we accept this reality, we will understand that “depressive episodes” are not something that can be stopped by human power. Even medicines take almost 2 weeks to take effect. So, we should allow him to have a depressive episode, allow him to cry, allow him to stay in bed, allow him to go to bed late, and allow him to not eat. In short, allow him to suffer and show the pain of the disease.

  • Accompany correctly.

We all know that people with depression need others around. Make no mistake. What they want is not 24-hour surveillance, but “I am always there when you need me”. Keeping distance is very important.  We don’t need to do anything on purpose, but we just need to let him know that he is not alone, even if depression has overwhelmed him. As long as he raises his arm, we will immediately hold his hand. It is enough to offer such a sense of security.

  • Offer daily assistance.

He may be unable to complete some small daily tasks due to the fatigue and powerlessness brought about by depression. We can help him within our ability.

  • Help for nothing in return.

You talk to him, and take care of him, but don’t expect him to respond. He may not answer you or cooperate with you, because he is concentrating his whole body to fight the disease. He has no time to care about you. But don’t feel aggrieved. When he gets better, he will thank you.

  • Be consistent.

If you have made up your mind, please be consistent and patient to the end; if you have no confidence to do so, please don’t intervene in his life. Or when you can’t stand it and change your mind, you may be the last straw.

12. Depression and alcohol

Alcohol dependence and depression are closely related, and the coexistence of the two is relatively common. According to some foreign research studies, nearly 30% of people who suffer from depression in their lifetime may be accompanied by alcohol dependence, and nearly 40% of patients who have been diagnosed with alcohol dependence may have depression. One view is that one disease may be a sudden factor for another disease. Another view is that the environment the patient is in has the same genetic factor. The third is that environmental and genetic factors have a certain relationship to the influence of these two diseases. So, these two diseases can happen in one person.

However, the relationship between alcohol dependence and depression is not particularly clear. Some patients with depression are not closely related to alcohol dependence. However, some depression is a secondary symptom of alcohol dependence, and some alcohol dependence is one of the clinical manifestations of depression. So, there are different analyses for different symptoms. But in real life, the formation and development of many people with alcohol dependence are closely related to emotion. We should carry out some targeted examinations for patients with depression or alcohol dependence to prevent missing diagnoses.【10】


13. What Is the Link Between Smoking and Mental Health Conditions?

According to a new study released by the University of Bristol in the UK, smoking may increase the risk of depression and schizophrenia. This shows that smoking not only harms physical health but also negatively affects mental health. A team led by scholars from the school analyzed the relevant data of about 462,000 people in the UK. Nearly 8% of them were smokers and 22% had a history of smoking.【11】

A large number of neuropsychological studies prove that smoking can cause mental disorders. Due to the stimulation of smoke during the smoking process, smoking can concentrate more attention and inhale more nicotine in the body. In the end, it can lead to memory, imagination, recognition ability, and intelligence levels decline.

Long-term smokers can develop tobacco dependence. If they don’t smoke for a long time, they may feel anxious, lose appetite, and easily anger. People who smoke excessively may feel dizzy and have a headache, and they may even faint or be in shock.