Schizophrenia spectrum disorder is a heterogeneous clinical syndrome marked by disruptions in perception, language, thinking, and social activity. The disorder is characterized by positive symptoms of hallucinations, delusions, disorganized thinking, and abnormal movements and negative symptoms such as loss of functioning in daily life, decreased emotional expression, diminished social engagement, and impaired concentration. Diagnosis is made when a patient demonstrates at least 2 of the above symptoms for at least 6 months and when these symptoms have begun to significantly impact daily functioning.

The disorder typically begins in late adolescence with an insidious onset, progressing from social withdrawal to an active phase consisting of perceptual perturbations, recurrent delusions, and hallucinations. Patients typically experience the first psychotic episode in the early- to mid-20s. Onset before adolescence is rare but can occur and is associated with a less favorable prognosis. Schizophrenia is typically a chronic disorder with significant impairments in functioning throughout the lifespan, although antipsychotics are up to 70% effective in reducing symptoms.

Risk factors for developing schizophrenia include winter birth, increasing paternal age, and family history of schizophrenia. Schizophrenia is seen in 6.6% of all first-degree relatives of the affected parent, and if both parents are affected, the risk of schizophrenia in the offspring is 40%.

Patients with this disorder may have an increased risk of various general medical conditions.