Psychotic disorders are a group of conditions - including schizophrenia - that are characterized by individuals having difficulty thinking clearly, making good decisions, distinguishing reality from imagination, and behaving appropriately.
This makes it very hard to handle daily life and social interactions, and if symptoms go untreated, individuals are at risk of harming themselves.
The underlying pathophysiology is still mostly a mystery, but there are some clues. Some psychotic disorders such as schizophrenia run in families, which suggests a genetic basis, and it’s also thought to be related to trauma, drug abuse, stress, infections, and autoimmune disorders.
Another clue is that some individuals benefit from antipsychotic medications which block the dopamine receptor D2, which suggests that for those people, excess dopamine levels may contribute to the disease.
In fact, interestingly, one of the most effective antipsychotic drugs, clozapine, is a weak D2 antagonist.
Now, according to DSM-V, psychotic disorders include seven main disorders distinguished by the duration and severity of symptoms, and the presence of mood episodes - either depressive, manic or hypomanic ones.
Depressive episodes persist for a two-week period and consist of diminished interest or pleasure in activities, significant weight loss or gain, inability to sleep or oversleeping, psychomotor agitation, feelings of worthlessness, decreased ability to think, and finally recurrent thoughts of death, or suicidality.
Manic and hypomanic episodes feature symptoms like grandiosity, racing thoughts, short attention, and rapid speech.
Schizophrenia is the most common psychotic disorders.
By comparison, conditions with less severe symptoms include schizotypal personality disorder, delusional disorder, and brief psychotic disorder.
On the flip side, there are the conditions with more severe symptoms like schizophreniform disorder, schizoaffective disorder, substance or medication-induced psychotic disorder, and psychotic disorder induced by another condition.