In schizophrenia, a person's perceptions, thoughts, mood and behaviour are significantly altered. The condition affects 15 out of every 100,000 people, with rates varying according to gender and age. Men under the age of 45 years have twice the rate of schizophrenia as women, but there is no difference after this age.

Psychological factors play an important role in schizophrenia and, while interventions such as psychological treatments can improve clinical outcomes, antipsychotics remain the primary treatment. The complexity of the disorder requires support from many different health agencies.

Symptoms

Symptoms can be divided into two categories (positive and negative) and two phases (prodromal and acute). The initial prodromal phase, often characterised by €negative€ symptoms such as social withdrawal and some deterioration in personal functioning, can be followed by an acute phase, which can see the development of €positive€ symptoms such as: 

• Hallucinations (e.g. hearing, seeing or feeling things that others do not)
• Delusions (e.g. markedly unusual or bizarre ideas)
• Behavioural disturbances (e.g. agitation and distress)
• Disorders of thinking so that speech becomes muddled and hard to understand.  

Positive symptoms may disappear or decrease after treatment, but it is common for negative symptoms, such as poor motivation, poor self-care and poor memory and attention, to remain problematic. 

Co-morbidities, such as depression, social anxiety disorder, post-traumatic stress disorder (PTSD), drug and alcohol misuse are common.

Diagnosis

There is no diagnostic test for schizophrenia, so assessment is by using diagnostic criteria. People vary considerably in their pattern of symptoms and problems. Recurrent episodes or relapses, often related to stress, adversity, social isolation and poor take-up of treatments, can be brief for some people but can last months or years for others. Only 14-20 per cent of people with schizophrenia will fully recover.