Approximately 90% of youths who complete suicide have a preexisting psychiatric illness. Of the following, the MOST commonly encountered illness is

Correct Answer: A

Rationale: Major depression is the most common psychiatric illness associated with completed suicides in youths.

Correct Answer: D

Rationale: Rubella is strongly associated with intracranial calcifications in affected infants. Other infections like cytomegalovirus and syphilis may also cause calcifications but are less characteristic.

Correct Answer: B

Rationale: The correct answer is 20%. Studies indicate that approximately 20% of children experience mental health issues at some point during their childhood.

Correct Answer: A

Rationale: Raynaud's phenomenon, characterized by vasospasm in response to cold or stress, is a common feature of systemic sclerosis.

Correct Answer: C

Rationale: Measles has an incubation period of approximately 10-14 days before symptoms like fever, cough, and Koplik spots appear.