7th November 2023

Disorders of Thought

Within the MSE, the subsection of thought content probably forms the largest section. Disorder of thought is divided into disorders of thought content (i.e. any abnormal beliefs the patient expresses) and disorders of thought form (i.e. the reasoning and manner in which their thoughts are expressed).

Two other components of thought disorder also exist, but these are more minor and don’t specifically appear within the MSE: control of thought and stream of thought. We discuss control of thought at the end of this chapter, and stream of thought is discussed in the next chapter.

The table below briefly describes each of these components. Don’t worry if some of these terms in the table are unfamiliar; they will all be discussed over the course of this chapter and the next.

When performing an MSE in clinical practice, one often refers to a thought stream within the component of thought form, but for academic purposes, the discrepancy is detailed in the table above.

Thought form will be discussed as the subject of the next chapter. For now, let’s look at the different disorders of thought content.

Thoughts of harming oneself

This is one of the most critical elements within thought content and contributes to a patient’s risk assessment.

The thoughts to harm oneself may vary in severity from superficial laceration (e.g. of the thigh with a razor blade) to thoughts of suicide, also known as suicidal ideation).

The patient may just present with self-harm or suicidal ideation; or, more concerningly, they may inform you of specific plans about how they would commit suicide; or at the most severe end of the spectrum, the patient may demonstrate suicidal intent whereby they have both a plan in mind and are demonstrating the intent to fulfil that plan.

Thoughts of harming others

Similar to the previous subsection, these thoughts may be associated with behavioural actions, and therefore, this also forms an essential part of an ongoing risk assessment.

Restricted thinking

The range of thought content is limited as the patient becomes fixated on one or a small number of topics. Any attempt at changing the topic of conversation is usually in vain as the patient will redirect the conversation back to their chosen topic.

Neologism

The formation of a newly coined word that’s meaning is unique to the patient. It is seen in schizophrenia, as well as in organic conditions such as stroke.

For example, ‘I was walking along the street, and when I looked down on the pavement, I saw a Fajunud.’

Thought control

Normally, the thoughts we experience are recognised as being our own. However, with thought control, also known as thought alienation, the thoughts experienced are under external control. Thought control and thought alienation have, in clinical practice, been replaced by these first rank symptoms of schizophrenia (Schneider, 1959):

• Thought insertion – The experience of foreign thoughts being put into one’s head by an external agency.
• Thought withdrawal – The experience of thoughts being taken out of one’s head by an external agency.
• Thought broadcasting – The experience of one’s thoughts being broadcast out loud so that others can hear and access them.

Overinclusive thinking

Patients with schizophrenia often demonstrate overinclusive thinking, that is, the tendency to incorporate ideas that are only tenuously related. For example, if asked about the essential elements of a pizza: ‘base, topping, or pizza box’, they might reply ‘pizza box’. This can be demonstrated by sorting tests. The lack of a meaningful bridge between two consecutive thoughts is called asyndesis.

Overvalued ideas

Defined by ICD-11 as unreasonable and sustained beliefs that are maintained with less than delusional intensity (i.e. the person is able to acknowledge the possibility that the belief may not be true).

Overvalued ideas are emotionally charged and sufficient to influence that person. They have been shown to differ from delusions in that people expressing overvalued ideas are more likely to identify what might modify their belief, they are more preoccupied, and they are more concerned about others’ reactions. Furthermore, overvalued ideas are more plausible, and their presence is more logical.

Interestingly, a comparative study on delusions and overvalued ideas found that ‘abrupt onset, implausible content and relative indifference’ were more reliable discriminating factors rather than the person’s insight (Mullen & Linscott, 2010).

Similar to delusions, over time, the beliefs may strengthen in intensity as the patient’s thinking becomes more concrete, and they find more of what they believe to be evidence to fuel these beliefs. Furthermore, they are similar to delusions in that they are not shared by others in their cultural or subcultural group.

Examples include hypochondriasis – an overvalued idea that one has a specific illness; and somatisation – an overvalued idea that one is experiencing a symptom or cluster of symptoms.

Preoccupations

Persistent worry or feelings of guilt about something are often seen in anxiety spectrum disorders and depression.

Obsessions

An obsession is any unwanted, intrusive thought, image, or urge that repeatedly enters the person’s mind. It is also known as a rumination. Obsessions induce high levels of anxiety in the patient.

It is important to understand the difference between obsessions and compulsions; the latter are obsessional motor acts that are compensatory, such as cleaning or staring. With compulsions, the patient often acknowledges that they don’t want to do the behaviour or action but that they feel compelled to do it to reduce the anxiety caused by the obsession.

An obsession is referred to as being ego-dystonic, meaning it is perceived by the patient as unreasonable and undesirable. For example, the most common obsession is that one is contaminated. An associated compulsion would be to wash repeatedly or repeat the phrase ‘I’ve showered’. It is most commonly associated with obsessive compulsive disorder; however, it may also be present in depression or schizophrenia.

Delusions

A delusion can be defined briefly as – A fixed, unshakeable belief held by a person contrary to evidence and not in keeping with their religious or cultural beliefs.

The content of delusions varies across time and culture. Some have remained consistent in their narrative, like delusions of love. Others, such as delusions of persecution, are continually evolving; for example, with technology such as mobile phones and the internet, the content has evolved to include beliefs around ‘hacking’ and ‘monitoring’.

Before we look at the different types of delusions, it is important to understand that delusions can be divided into two types, according to Karl Jaspers (the 20th Century German-Swiss psychiatrist and philosopher):

Primary delusions

Delusions that arise ‘out of the blue’ with no psychopathology like a mood disorder. In other words, we cannot understand how they were formed. They are only present in schizophrenia. To complicate it slightly further, according to Jaspers, primary delusions can be further subcategorised into 4 types:

Autochthonous delusion.

These refer to delusions that arise spontaneously ‘out of the blue’ with nothing preceding it.

Delusional percept.

This is when a normal perception is interpreted with a delusional meaning and holds a significance which is not understandable to others. Unlike an autochthonous delusion, there are 2 stages: the perception and the interpretation. For example, a person sees two freckles near each other on his skin, declaring that he has been bitten by a poisonous snake and refusing to acknowledge any other explanation. It is a first rank symptom of schizophrenia. A sudden delusional idea may occur, in which a new delusion becomes fully formed in the patient’s mind.

Delusional atmosphere.

This refers to the patient feeling that ‘something strange is going on’. They feel like there are things happening around them that are building up and about to present themselves in some sort of significant manner. It may be exciting or terrifying. The mood of the atmosphere is significant, and patients may begin their journey of psychosis with a delusional mood: they have a sensation that something is not quite right. They may start to perceive certain senses more strongly, and they might appear perplexed or confused as they struggle to piece together this new world around them. When a delusion is finally formed, it might be a relief to the patient that finally, now, they have made sense of what they have been experiencing, of course, in their distorted reality.

Delusional memory.

This is simply the delusional interpretation of a normal memory. For example, a patient experiencing auditory hallucinations in the form of voices asserting that these voices arose after a radio emitter was placed in his ear by a doctor last year. In fact, a grommet was inserted into that ear 20 years ago whilst the patient was a child for recurrent otitis media. The patient continues to demand CT scans of his head so that we can identify and remove the emitter.

Primary delusions are more common in acute schizophrenia. These will often develop to become increasingly elaborate, evolving to become enmeshed together. This concept is known as a systematised delusion. Primary delusions are less common in chronic schizophrenia, which is more characterised by secondary delusions, which we shall discuss now.

Secondary delusions

Delusions that arise from some form of morbid experience, for example, depression, hallucinations, psychosocial stressors or abnormal personality traits (like a paranoid personality giving rise to persecutory delusional beliefs). In other words, the delusion is understandable, given the current circumstances, because of a pervasive mood state. Secondary delusions occur in many conditions, including schizophrenia and bipolar affective disorder. They can also occur in organic conditions such as drug intoxication, withdrawal and epilepsy. For example, a patient experiencing a manic episode who believes they are a rockstar can be understood as their manic state invoking an expansive and elated mood. Conversely, a depressed patient with psychotic features may believe they are rotting inside.

Now that you have an understanding of primary and secondary delusions, the next part of this chapter looks at specific delusions that are likely to come up in the MRCPsych exam.

References

• Prathap, S. (2019). SPMM Smart Revise. SPMM Course.
• Schneider, K. (1959). Clinical Psychopathology. New York: Grune & Stratton
• World Health Organization. (2019). ICD-11: International classification of diseases (11th revision).
• Oyebode, F. (2015). Sims’ Symptoms in the Mind. Textbook of Descriptive Psychopathology. Elsevier: 5th Ed.
• Mullen, R., Linscott, R. (2010). A comparison of delusions and overvalued ideas.The Journal of Nervous and Mental Disease. 198(1): 35-8.
• Jaspers, K. Allgemeine Psychopathologie. Berlin: Springer. 1913. English translation of the 7th edition General Psychopathology. Baltimore. Johns Hopkins University Press; 1997.