Which of the following best describes an illusion?

A. Sudden onset of psychotic symptoms in less than a month. According to the DSM-5, brief psychotic disorder is characterized by a sudden onset of delusions, hallucinations, disorganized speech, or disorganized behavior that lasts at least one day but less than one month, with eventual full recovery.

B. Sudden onset of psychotic symptoms in less than two months. The DSM-5 criteria do not define brief psychotic disorder with a two-month duration. If symptoms persist beyond one month, another diagnosis, such as schizophreniform disorder, may be considered.

C. Sudden onset of psychotic symptoms in less than one year. Psychotic symptoms lasting up to one year are more indicative of schizophrenia or schizoaffective disorder, not brief psychotic disorder.

D. Sudden onset of psychotic symptoms in less than six months. Psychotic symptoms lasting longer than one month but less than six months are consistent with schizophreniform disorder, rather than brief psychotic disorder.

A. Fetal alcohol syndrome (FAS) is a leading preventable cause of intellectual disability. Prenatal alcohol exposure disrupts brain development, leading to cognitive impairment, behavioral problems, and facial abnormalities.

B. Down syndrome (trisomy 21) is a genetic disorder that causes intellectual disability, developmental delays, and characteristic physical features. It results from an extra copy of chromosome 21, affecting brain development and cognitive function.

C. Serotonin syndrome is an acute, life-threatening condition caused by excessive serotonin activity due to medication overdose or drug interactions (e.g., SSRIs, MAOIs, MDMA). Symptoms include hyperreflexia, autonomic instability, and altered mental status, but it does not cause intellectual disability.

D. Fragile X syndrome is a genetic disorder caused by a mutation in the FMR1 gene on the X chromosome. It is the most common inherited cause of intellectual disability, leading to cognitive impairments, social anxiety, and hyperactivity, often resembling autism spectrum disorder (ASD).