Schizophrenia has long been the heartland of psychiatry, but can be as confusing now as it was 100 years ago. Lay opinion is that schizophrenia is commensurate with hearing voices and paranoia, but this is not true. Hearing voices and paranoia are non-specific phenomena which can occur in normal psychic life.

So what exactly is schizophrenia? Well it is also not commensurate with psychosis. In fact, there is a long list of conditions in which psychosis can occur (Figure 1).

Psychosis we can define as a fundamental shift in a person’s experience of lived reality, affecting the highest faculties of mental life – perception, thinking, beliefs, self-hood.

Lay opinion also makes the mistake in formulating the psychotic shift as breach from consensual reality, the shared reality of the group. It is not. The psychotic shift is a breach from one’s previous way of being in the world. One aspect of psychosis is key. The sufferer is unaware of the falsity of their new reality, a fact which is obvious to friends and family.

But what is schizophrenia?

Again we return to the question, what is schizophrenia? Here we grasp for an answer. The most important point is that schizophrenia involves a loss. Not just a loss of the previous way of perceiving and thinking about the world, but something deeper. The loss encompasses – human relationships, interests, intellectual pursuits, ambition, motivation, emotional life. At its most extreme, it is the spark of mental life itself which is lost (or markedly impoverished) – the personality, drive, speech, thinking, the will.

In modern psychiatry such phenomena are referred to as the negative syndrome, which obviously denotes loss. The negative syndrome maps onto poorer intellectual abilities, across multiple domains – working memory, episodic memory, processing speed, social cognition – and is associated with functional disability in daily life.(Figure 2).

We can recap. Voices and paranoia are not commensurate with psychosis. Psychosis occurs in a multitude of disorders, not just schizophrenia. Finally, schizophrenia is so disabling because of the loss (or diminution) of all those aspects which make human mental life so special and unique.

Further posts in this series:

What causes schizophrenia?

Future posts in this series:

What happens to the nervous system in schizophrenia?

The prognosis of schizophrenia.

How is schizophrenia treated?