Memory is of three types: sensory, short term and long term. It can be compared to a sieve with holes of varying sizes to assist in separating material that is relevant from that which is irrelevant. The first type of memory, sensory memory, is registered for each of the senses and its purpose is to facilitate the rapid processing of incoming stimuli so that comparisons can be made with material already stored in short- and long-term memory. Since there are numerous stimuli bombarding the individual, selective attention allows for the sifting of relevant material from sensory memory for further processing and storage in short-term memory. As a consequence, most sensory memories fade within a few seconds. Short-term memory, also called working memory, allows for the storage of memories for much longer than the few seconds available to sensory memory. Short-term memory aids the constant updating of one’s surroundings.

These are changes in perception that are the result of a change in the intensity and quality of the stimulus or the spatial form of the perception.

Karl Jaspers, a psychiatrist, theologian and philosopher, is the father of psychopathology. His work General Psychopathology (translated 2013) is a classic in the psychiatric literature. He believed that mental illness, in particular psychosis, should be evaluated with regard to the abnormal phenomena that are present – for example, hallucination, delusions, thought disorder – rather than to their content. The latter (content) was the focus of the psychoanalytic school who argued that content was a clue to underlying traumas and issues that may have contributed to the person’s current state. So whether the content of a delusion was persecutory or guilt-laden, Jaspers believed, was less important than the presence per se of the delusion. Thus, he was distinguishing between form (primary or secondary, systematised or non-systematised, etc.) and content (e.g., persecutory, guilt and nihilistic).

Recent decades have seen a considerable renaissance of scienti?c interest in the study of human consciousness. For the purposes of descriptive clinical psychopathology, consciousness can be simply de?ned as a state of awareness of the self and the environment. Disorders of consciousness are associated with disorders of perception, attention, attitudes, thinking, registration, and orientation. Consciousness can be changed in three basic ways: it may be dream-like, depressed, or restricted. This chapter outlines these different types of disturbance of consciousness, including delirium, twilight states, and dissociative fugue, among other conditions. The chapter concludes with suggested questions for eliciting specific symptoms in clinical practice, in addition to standard history-taking and mental state examination.

It is customary to distinguish between feelings and emotions. A feeling can be defined as a positive or negative reaction to some experience or event and is the subjective or experiential aspect of emotion. By contrast, emotion is a stirred-up state caused by physiological changes occurring as a response to some event and which tends to maintain or abolish the causative event. The feelings may be those of depression, anxiety, fear and so on. Mood is a pervasive and sustained emotion that colours the person’s perception of the world. Descriptions of mood should include intensity, duration and fluctuations as well as adjectival descriptions of the type. Affect, meaning short-lived emotion, is defined as the patient’s present emotional responsiveness. It is what the doctor infers from the patient’s body language, including facial expression, and it may or may not be congruent with mood. It is described as being within normal range, constricted, blunt or flat.

Psychiatric illness may be associated with objective or subjective motor disorders. This chapter is chie?y devoted to objective motor disorders, but subjective motor disorders may also occur. It is difficult to classify motor disorders because although clear-cut individual motor signs (such as stereotypies) can be treated as if they were neurological symptoms, it is much more difficult to classify more complicated patterns of behaviour. Nonetheless, motor disorders can be broadly grouped into the following categories: (a) disorders of adaptive movements; (b) disorders of non-adaptive movements; (c) motor speech disturbances; (d) disorders of posture; (e) abnormal complex patterns of behaviour; and (f) movement disorders associated with antipsychotic medication. This chapter explores and explains these different categories of motor disorder in the context of psychiatric illness. The chapter concludes with suggested questions for eliciting specific symptoms in clinical practice, in addition to standard history-taking, mental state examination and physical examination.

Any discussion of the classification of psychiatric disorders should begin with the frank admission that any definitive classification of disease must be based on aetiology. Until we know the causes of the various mental illnesses, we must adopt a pragmatic approach to classification that will best enable us to care for our patients, to communicate with other health professionals and to carry out high-quality research.

In physical medicine, syndromes existed long before the aetiology of these illnesses were known. Some of these syndromes have subsequently been shown to be true disease entities because they have one essential cause. Thus, smallpox and measles were carefully described and differentiated by the Arabian physician Rhazes in the tenth century. With each new step in the progress of medicine, such as auscultation, microscopy, immunology, electrophysiology and so on, some syndromes have been found to be true disease entities, while others have been split into discrete entities, and others still jettisoned.

Recent decades have seen a revival of interest in the study of the self, self-awareness and various changes in self-awareness, especially in the context of mental illnesses, such as schizophrenia. This chapter outlines the psychopathology of various disturbances of awareness of self-activity, including depersonalisation, loss of emotional resonance, disturbances in the immediate awareness of self-unity, disturbances in the continuity of the self and disturbances of the boundaries of the self. It also explores theory of mind, consciousness and schizophrenia, which represent areas of growing research interest. The chapter concludes with suggested questions for eliciting specific symptoms in clinical practice, in addition to standard history-taking and mental state examination.

Disorders of thought include disorders of intelligence, disorders of the stream of thought, disorders of thought possession and obsessions, and disorders of the content and form of thinking. This chapter outlines disorders of intelligence, disorders of thinking, disorders of thought tempo, disorders of the continuity of thinking and disorders of the content of thinking. It presents descriptions of obsessions and primary and secondary delusions, as well as detailed examinations of specific delusions of persecution, infidelity, love, grandiosity, ill-health, guilt, nihilism and poverty. Speech disorders are also explored, along with aphasias. The chapter concludes with suggested questions for eliciting specific symptoms in clinical practice, in addition to standard history-taking and mental state examination. Disorders of thought and speech are central to the manifestation and diagnosis of many psychiatric disorders, including schizophrenia, and this chapter provides both descriptions and explanations of key signs and symptoms in this field.