It is common that on some occasions, and especially under high levels of stress, we find ourselves faced with the firm belief that someone is watching us, that someone is following us or that someone is talking about us even though this is not true.

However, when these ideas flood the person’s mind and he is not able to see reality we can talk about the known delusions . Throughout this article we will go deeper into the nature of this experience, as well as into its causes, types and differences with other false beliefs.

What are delusions?

Within the field of psychopathology , delirium is understood as a false belief or idea that the patient accepts with total conviction , despite the fact that external evidence or proofs prove the opposite. Although it has not yet been possible to generate a totally accepted and satisfactory description of this concept, the above description would be one of the most approximate.

Despite its pathological characteristics, delirium is not considered a mental illness or disorder in itself , but rather would be a symptom of a wide variety of psychological conditions such as bipolar disorder, schizophrenia, mania, or psychotic depression.

During the course of the delirium the person’s mental state undergoes a great deal of change. These cause the patient to experience feelings of confusion and altered behaviour .

Other manifestations or problems typical of delusional states are:

  • Abrupt changes between states of lucidity and unconsciousness
  • Loss of contact with reality .
  • Altered attention and memory.
  • Emotional ups and downs.
  • Muscle control problems.
  • Sleep disturbances.

Diagnostic criteria

However, as specified in the previous point, delusions do not constitute a clinical disorder, but are part of a larger pathological picture. However, they must meet a series of special and specific requirements in order to be considered as such.

Some authors and researchers have developed a series of constructs that define delirium. These dimensions or constructs are given in the form of continuations that start from what is considered a normal belief, to a pathological one , and are key to being able to differentiate delirium from other types of beliefs or erroneous ideas. These characteristics are the ones we’ll see next.

1. Fixed and unchangeable beliefs or ideas

The delusion must be maintained over time ; it is unlikely that it can be modified or corrected regardless of the evidence against it.

2. Intense conviction

A delusion is a firmly held idea. That is, the person believes blindly in an idea or concrete event.

3. Lack of cultural supports

It is necessary to specify that the idea maintained by the patient cannot be shared by other people or cultural groups . This means that for the belief to be considered irrational it cannot be shared or accepted by the rest of the reference society.

4. Excess concern

Unlike other false or irrational beliefs, in delusions the person presents a great concern or rumination of the delusional idea, which implies an important psychological wear since the patient thinks about it in an obsessive way.

5. Degree of plausibility

The latter criterion refers to the degree of probability that the idea can be real. This degree of plausibility can vary from one delusion to another. This means that while in some cases it is easy to detect the impossibility of the delusional idea, in others it may be totally plausible but false .

What are their causes?

Delusions and delusional ideas have as their origin a series of mental and psychological disorders that accompany and shape them. These psychological conditions are:

  • Paranoid disorders.
  • Paranoid, schizoid and schizotypal personality disorders.
  • Schizophrenia .
  • Affective disorders such as psychotic depression and mania

However, they can also be part of other alterations of organic origin derived from the consumption of drugs and alcohol in abuse, as well as from detoxification processes and as a secondary reaction to certain drugs.

What kinds of delusions are there?

Despite the large number of delusions, they can be categorized and classified according to their content. Below are some of the most frequent and well known.

1. Paranoid delirium

In the case of paranoid ideas, the person is convinced that a person or group wants to cause him/her some kind of harm , be it physical, psychological or social.
This delusion may be based on the idea that others want to kill him or that someone is trying to drive him crazy.

2. Delirium of persecution

People suffering from delusions of persecution strongly claim that someone is persecuting them, or even that there is a conspiracy against them. This persecution may be either in the street, directly, or in a more veiled way: patients may think that they are entering their home, opening their mail or searching their mobile devices or computers.

3. Delirium of grandeur

The content of this delirium manifests itself through an excessive self-evaluation of the abilities and powers of the patient; who attributes to himself special abilities as well as a great consideration of his own identity.

4. Reference Delirium

As the name implies, in the delusion of reference the patient believes that certain events, phrases or statements of others have to do with him or have a special significance that has to do with him.

It is common for these patients to think that the media and others are sending them all kinds of messages.

5. Somatic Delirium

In the latter case, the patient shows the conviction that he is sick or his body is getting sick . In the same way, he may perceive a series of false changes or abnormalities in it.
These are only a small sample of what is really a long list of delusions and delusional ideas.

6. Others

Other well-known delusions are:

  • Control delirium.
  • Metacognitive delirium.
  • Delirium of guilt or sin.
  • Celotypical delirium .
  • Delirium of false identification.
  • Erotomaniacal delirium.

What’s the difference between a delusion and a hallucination?

The fact that they are often presented together and share certain characteristics makes delusions and hallucinations often confusing .
However, once we know what the delusions are, it is much easier to differentiate them.

Unlike delusions, hallucinations are an original product of the person’s mind. That is, they do not really exist in reality or in the external world of reality. Furthermore, just as a delusion consists of an idea, hallucinations can be auditory, visual, tactile, or even taste experiences. Therefore, the main difference between both concepts is that hallucination is a totally original product invented by the person’s mind, whereas delirium would be a distortion of an external stimulus .

For example, in a delirium the person may perceive a real stimulus such as radio; however the mind of the person distorts the message or interprets it as a kind of communication for him. While in hallucination the auditory stimulus would be completely invented by the mind, it cannot be perceived by anyone else.

Delirium would consist of a belief or misinterpretation of reality based on a real fact, situation or stimulus. However, both concepts have one thing in common. In this case it is that the patients are fully convinced of the reality and veracity of their ideas or beliefs.