Diagnosing schizophrenia in the ICD

1. Schizophrenia is a serious mental health condition that changes how a person thinks, feels and experiences the world around them.
2. Its clinical characteristics are set out in the International Classification of Diseases, published by the World Health Organization, and the current version is ICD-11.
3. ICD-11 requires at least two of its listed symptoms, present for at least one month, before schizophrenia is diagnosed.
4. At least one of those two has to come from the positive group, so negative symptoms on their own are not enough for the diagnosis.

How the diagnosis is reached

1. The symptoms must also not be explained by something else, such as a brain tumour, a drug, or the side effects of medication.
   1. A psychiatrist therefore takes a full history and rules out the other possible causes.
2. ICD-11 dropped the older subtypes such as paranoid and catatonic, so there is now one diagnosis rated on which symptoms a person currently has.

Positive symptoms

1. Hallucinations
   1. A hallucination is a sensory experience of something that is not there, and in schizophrenia it is most often auditory.
   2. A person may hear one or more voices commenting on what they are doing, and the voice sounds as real to them as any other sound in the room.
2. Delusions
   1. A delusion is a belief held firmly even when there is clear evidence against it.
   2. Common forms are delusions of persecution, a belief that the person is being followed or plotted against, and delusions of grandeur, a belief that they have special powers or importance.
3. Disorganised thinking
   1. Thoughts jump between loosely connected ideas, which shows up as speech that a listener cannot follow, and in severe cases as scrambled speech called word salad.
4. Experiences of influence, passivity and control
   1. Thoughts, feelings or movements feel as though something outside the person is controlling them.
   2. ICD-11 includes thought insertion, where a thought feels planted from outside, and thought broadcasting, where a person believes others can hear their thoughts.
5. Disorganised behaviour and psychomotor disturbance
   1. Behaviour becomes odd or aimless, such as wearing a winter coat in July or laughing with no trigger.
   2. Psychomotor signs include holding one unusual posture for a long time, or barely moving and speaking at all.

Negative symptoms

1. Avolition
   1. Motivation and energy drop, so starting and finishing everyday tasks such as washing, cooking or getting to college becomes very hard.
2. Blunted or flat affect
   1. The face, voice and gestures show much less feeling, so a person can sound flat while describing something upsetting.
3. Alogia
   1. Speech becomes sparse, and answers shrink to a few words even when the question invites much more.
4. Asociality
   1. A person spends far less time with friends and family and stops seeking company out, because the drive to socialise is itself reduced.
5. Anhedonia
   1. Things that used to be enjoyable stop giving any pleasure, including food, music and a match they once never missed.
6. Symptoms come and go over time, and with treatment and support many people manage the condition well or recover from it.
7. Dangerousness is not one of the clinical characteristics, and people with schizophrenia are more likely to experience violence than to commit it.

Turning this into marks

1. When two symptoms are asked for, make them genuinely separate rather than one symptom rephrased.
2. Use the clinical term from the ICD, so avolition rather than laziness, because an everyday description does not secure the knowledge mark.
3. Where a question asks how the diagnosis is made, give the threshold of two symptoms for one month with at least one of them positive.
4. The mark most often lost is giving two positive symptoms when the question asked for one of each type.