A delusion is a belief held with strong conviction despite superior evidence to the contrary. Delusions typically occur in the context of neurological or mental illness, although they are not tied to any particular disease and have been found to occur in the context of many pathological states (both physical and mental). However, they are of particular diagnostic importance in psychotic disorders including schizophrenia, paraphrenia, manic episodes of bipolar disorder, and psychotic depression.
Delusional disorder, previously called paranoid disorder, is a type of serious mental illness called a “psychosis” in which a person cannot tell what is real from what is imagined. The main feature of this disorder is the presence of delusions, which are unshakable beliefs in something untrue. People with delusional disorder experience non-bizarre delusions, which involve situations that could occur in real life, such as being followed, poisoned, deceived, conspired against, or loved from a distance. These delusions usually involve the misinterpretation of perceptions or experiences. In reality, however, the situations are either not true at all or highly exaggerated.
People with delusional disorder often can continue to socialize and function normally, apart from the subject of their delusion, and generally do not behave in an obviously odd or bizarre manner. This is unlike people with other psychotic disorders, who also might have delusions as a symptom of their disorder. In some cases, however, people with delusional disorder might become so preoccupied with their delusions that their lives are disrupted.
Delusions are categorized into four different groups:
- Bizarre delusion: A delusion that is very strange and completely implausible; an example of a bizarre delusion would be that aliens have removed the reporting person’s brain.
- Non-bizarre delusion: A delusion that, though false, is at least possible, e.g., the affected person mistakenly believes that he is under constant police surveillance.
- Mood-congruent delusion: Any delusion with content consistent with either a depressive or manic state, e.g., a depressed person believes that news anchors on television highly disapprove of him, or a person in a manic state might believe she is a powerful deity.
- Mood-neutral delusion: A delusion that does not relate to the sufferer’s emotional state; for example, a belief that an extra limb is growing out of the back of one’s head is neutral to either depression or mania.
Types of delusional disorders
Diagnosis of a specific type of delusional disorder can sometimes be made based on the content of the delusions.Diagnostic and Statistical Manual of Mental Disorders (DSM) enumerates seven types:
- Erotomanic type (erotomania): delusion that another person, often a prominent figure, is in love with the individual. The individual may breach the law as he/she tries to obsessively make contact with the desired person.
- Grandiose type: delusion of inflated worth, power, knowledge, identity or believes he/she to be a famous person, claiming the actual person is an impostor or an impersonator.
- Jealous type: delusion that the individual’s sexual partner is unfaithful when it is untrue. The patient may follow the partner; check text messages, emails, phone calls etc. in an attempt to find “evidence” of the infidelity.
- Persecutory type: This delusion is a common subtype. It includes the belief that the person (or someone to whom the person is close) is being malevolently treated in some way. The patient may believe that he/she has been drugged, spied-on, harassed and so on and may seek “justice” by making police reports, taking court action or even acting violently.
- Somatic type: delusions that the person has some physical defect or general medical condition
- Mixed type: delusions with characteristics of more than one of the above types but with no one theme predominating.
- Unspecified type: delusions that cannot be clearly determined or characterized in any of the categories in the specific types.
Delusional Disorder Themes
In addition to these categories, delusions often manifest according to a consistent theme. Although delusions can have any theme, certain themes are more common. Some of the more common delusion themes are:
- Delusion of control: This is a false belief that another person, group of people, or external force controls one’s general thoughts, feelings, impulses, or behavior.
- Cotard delusion: This is a false belief that one does not exist or has died.
- Delusional jealousy: A person with this delusion falsely believes that a spouse or lover is having an affair, with no proof to back up their claim.
- Delusion of guilt or sin (or delusion of self-accusation): This is an ungrounded feeling of remorse or guilt of delusional intensity.
- Delusion of mind being read: The false belief that other people can know one’s thoughts.
- Delusion of thought insertion: The belief that another thinks through the mind of the person.
- Delusion of reference: The person falsely believes that insignificant remarks, events, or objects in one’s environment have personal meaning or significance.
- Erotomania A delusion in which someone falsely believes another person is in love with them.
- Grandiose religious delusion: The belief that the affected person is a god, or chosen to act as a god.
- Somatic delusion: A delusion whose content pertains to bodily functioning, bodily sensations, or physical appearance. Usually the false belief is that the body is somehow diseased, abnormal, or changed. A specific example of this delusion is delusional parasitosis: a delusion in which one feels infested with insects, bacteria, mites, spiders, lice, fleas, worms, or other organisms. Affected individuals may also report being repeatedly bitten. In some cases, entomologists are asked to investigate cases of mysterious bites. Sometimes physical manifestations may occur including skin lesions.
- Delusion of poverty: The person strongly believes that he is financially incapacitated. Although this type of delusion is less common now, it was particularly widespread in the days before state support.
Persecutory delusions are the most common type of delusions and involve the theme of being followed, harassed, cheated, poisoned or drugged, conspired against, spied on, attacked, or otherwise obstructed in the pursuit of goals. Persecutory delusions are a condition in which the affected person wrongly believes that they are being persecuted. Specifically, they have been defined as containing three central elements: The individual thinks that
- harm is occurring, or is going to occur.
- the persecutor(s) has (have) the intention to cause harm.
- they are constantly being prejudged or profiled.
According to the DSM-IV-TR, persecutory delusions are the most common form of delusions in schizophrenia, where the person believes they are “being tormented, followed, sabotaged, tricked, spied on, or ridiculed. In the DSM-IV-TR, persecutory delusions are the main feature of the persecutory type of delusional disorder. When the focus is to remedy some injustice by legal action, they are sometimes called “querulous paranoia.”
- Intimate partner: this stalker, the most common type, is a partner or more usually an ex-partner who can’t and won’t accept that a relationship has come to an end. They can’t let go.
- Vengeful stalker: this is the most dangerous type whose mission is to get even and/or take revenge. Mostly male, he has a grudge and he’s going to do something about it. The vengeful stalker may never have met his victim, who may be a politician, council official, boss, organization, etc.
- Delusional stalker: this one has a history of mental illness which may include schizophrenia or manic depression. The schizophrenic stalker may have stopped taking his or her medication and now lives in a fantasy world composed of part reality and part delusion which he or she is unable to differentiate. If they’re not careful, targets of the delusional stalker are likely to be sucked in to this fantasy world and start to have doubts about their own sanity, especially if the stalker is intelligent, and intermittently and seamlessly lucid and “normal”.
- Erotomaniac: this stalker is also delusional and mentally ill and believes he or she is in love with you and will have created an entire relationship in their head.
- Harasser stalker: some stalker types like to be the center of attention and may have an attention-seeking personality disorder; they may not be stalkers in the strict sense of the word but repeatedly pester anyone (especially anyone who is kind, vulnerable or inexperienced) who might be persuaded to pay them attention. If they exhibit symptoms of Munchausen Syndrome they may select a victim who they stalk by fabricating claims of harassment by this person against themselves.
- Cyber-stalkers and love rats: again, these may not be stalkers in the strict sense of the word but they have many similar characteristics. Cyber stalkers and love rats surf the web with the intention of starting relationships and may have several simultaneous relationships. The targets of a cyber-stalker may know little about the person they are talking to (other than what they’ve convincingly been fed) and be unaware of a trail of other targets past and present.
- Troll. The Troll’s purpose is to be given more credibility than (s)he deserves, and to suck people into useless, pointless, never-ending, emotionally-draining, ranting discussions full of verbal loops and “word labyrinths”, playing people against each other, hurting their feelings, and wasting their time and emotional energy.
- It’s common for stalkers to exhibit characteristics of more than one of these stalking types.