Major depression, one of the common depression subtypes, affects 6.7 percent of the US adult population, or 14.8 million people, according to the National Institute of Mental Health (NIMH). This condition is characterized by persistent sadness and other mood changes, which can alter how the patient sees the world. Without treatment, depression can continue to cause cognitive distortions in the patient, such as negative filtering, personalization and catastrophizing.
Negative Filtering
Filtering is one form of cognitive distortion where the patient takes "the negative details and [magnifies] them while filtering out all positive aspects of a situation," according to John M. Grohol, Psy.D, author of the article "15 Common Cognitive Distortions." Negative filtering can become severe in depression, as the patient has a constantly low mood and can focus solely on the negative aspects of her life. The Mayo Clinic notes that during a depressive episode, the patient feels sad or unhappy and can get frustrated over small matters.
Personalization
With personalization, the patient blames himself when things go wrong in his life, according to the Mayo Clinic. The self-blame can lead the patient to feel guilty, even if there is no reason for him to feel that way. For example, if two friends get into a serious argument, the patient may say it was his fault, even if he was not involved in the fight at all. The blame and guilt that stems from the personalization can cause the patient to feel worthless, which can increase his feelings of sadness.
Catastrophizing
A depressed person with a catastrophizing cognitive distortion expects the worse to happen and can blow small events out of proportion. As with negative filtering and personalization, the patient sees the world in a negative light and blames herself for anything that may have gone wrong. The NIMH notes that catastrophizing can cause the patient to feel pessimistic. The patient may also become irritable or cry for no apparent reason. The excessive guilt, self-blame and worthlessness from the cognitive distortions can lead to suicide, where the patient feels life is no longer worthwhile and that nothing good lies ahead.
