Schizophrenia is characterised by a range of positive and negative symptoms. Positive symptoms are those added to a normal experience, such as hallucinations - unreal perceptions like hearing voices or feeling insects crawling on the skin (formication) - and delusions, which are irrational beliefs, such as delusions of persecution (believing others want to harm you) or grandiosity (believing you are famous or powerful). Another key positive symptom is disordered thinking, which may involve jumbled or incoherent speech, or thought insertion, where the person believes external forces are putting thoughts into their mind. Negative symptoms refer to a loss or reduction of normal functions. These include alogia (poverty of speech), avolition (lack of motivation or goal-directed behaviour), and anhedonia (inability to experience pleasure). Individuals may also show flatness of affect, with reduced emotional…
