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Common Causes of Clinical Depression

“What is depression, Dr. Rayel?” “Any hope for me?” “Is it a chemical imbalance?” “Is there any effective treatment?”

Many individuals and their family members have asked me about clinical depression. Usually, I explain that clinical depression has different causes and treatment varies depending on the cause.

Let me describe one of the most common illnesses called major depression (officially named major depressive disorder). Major depression is a medical disorder characterized by the presence of either a depressed mood or lack of interest to do usual activities occurring daily for at least two weeks. Like any medical disorders, this illness has associated physical features such as impaired energy, loss of appetite, sleep problem, and inability to focus. Some depressed individuals even lose their desire to be physically intimate with their spouses.

In addition, some eventually suffer from feelings of hopelessness, helplessness, and worthlessness. Frequent crying episodes and irritability are not uncommon.

Children and teenagers present differently compared to adults. Although children also feel depressed like adults, they also experience agitation, clingy behavior, and physical complaints such as stomach upset and headache. Meanwhile, teenagers show behavioral changes when they suffer from clinical depression. Apart from depressed mood, they also present with antisocial behavior such as truancy, aggression, substance abuse, and promiscuity. As a result, their academic performance suffers.

If left untreated, depressed individuals get worse and become socially withdrawn. Moreover, about 15% of depressed individuals become suicidal and occasionally, homicidal. Others develop psychosis - hearing voices (hallucinations) or having false beliefs (delusions) that people are out to get them.

What about manic-depression?

Manic-depression (officially called bipolar disorder) is a psychiatric disorder characterized by the presence of major depression (as described above) and at least one episode of mania that lasts for at least a week. When mania is present, individuals show significant excitement or extreme irritability. In addition, they become talkative and loud. At night, they are busy doing things such as making phone calls, cleaning the house, and starting new projects because they don’t need much sleep. In fact despite apparent lack of sleep, they are still energetic in the morning - ready to pursue new endeavors.

Because they feel extremely good when manic, they involve in unreasonable business deals and unrealistic personal projects. Some even become hypersexual - wanting to have sex several times a day. One-night stands can happen resulting in marital conflict and medical problems such as HIV. Others develop delusions (false beliefs) that they have special powers.

The big difference between major depression and manic-depression is the presence of mania which has serious treatment implications.

Another cause of depression is dysthymia (officially named as dysthymic disorder). Despite being a low-level depression, it is just as distressing as major depression and manic-depression. It is usually associated with poor self-esteem and lack of interest to pursue worthwhile goals. Physical features such as sleep problem and poor concentration can also happen.

How about street drugs and medical problems?

Medical disorders, alcohol and street drugs, and prescribed medications can precipitate clinical depression. Stroke, hypothyroidism, multiple sclerosis, vitamin B-12 deficiency, pancreatic cancer, Parkinson’s disease, and ischemic heart disease are examples of medical disorders associated with depression. Based on studies, those with medical problems that suffer from depression have more functional impairment and are more difficult to treat compared to those who are not depressed.

About 50% of hospitalized stroke patients suffer from depression within a year. Among Parkinson’s disease patients, about 50% suffer from moderate to severe depression while around 30% develop mild depression.

Alcohol is a depressant so those who often drink to feel better get worse sooner. Also after the initial “high”, cocaine and amphetamine users eventually feel depressed, irritable, and suicidal especially if these drugs are withdrawn abruptly. Even medications prescribed for medical problems such as beta-blockers or benzodiazepines may cause depression.

As clinicians, our challenge is to know the real cause of depression that afflicts our patients. Since these illnesses significantly impair functioning, it is crucial to address the difficulties right away. However, only through careful assessment and detailed examination that health professionals can give proper treatment.

In summary, clinical depression can be caused by many medical disorders. It is a serious illness that impacts the family, the workplace, and the community. Knowing the cause is the key to effective treatment.

by Michael G. Rayel, MD -

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Dr. Michael G. Rayel - author, game inventor, and psychiatrist - has created the Oikos Game Series to promote emotional health and has provided EQ Webinar for parenting, personal, and career success. For more info, visit or