Table 1.

Core symptoms and common characteristics of psychiatric disorders. Ticks and crosses correspond to characteristics commonly observed or absent in the given diagnosis, respectively

Diagnosis	Symptoms	Common characteristics
		Psychosis	Depression	Cognitive deficits	Childhood onset	Late adolescence/early adulthood onset
Intellectual disability	Severe deficits in intellectual functioning and adaptive skills, usually established with an IQ score < 70.	✘	✘	✓	✓	✘
Autism spectrum disorder	Developmental disorders with abnormal verbal and nonverbal communication and social interaction, and repetitive behaviors. Symptoms range from moderate to severe.	✘	✘	✓	✓	✘
Attention-deficit hyperactivity disorder	Persistent patterns of inattention and/or hyperactivity, impulsive behavior, which disrupt social, academic or occupational functioning.	✘	✘	✘	✓	✘
Schizophrenia	Positive (hallucinations, delusions), negative (diminished emotional expression), cognitive decline, disorganized thinking.	✓	✘	✓	✘	✓
Bipolar disorder	Episodes of extreme high (mania) and low (depression) moods.	✓	✓	✘	✘	✓
Major depressive disorder	Persistent feelings of sadness and hopelessness. Inability to concentrate and diminished interest in most activities.	✘	✓	✘	✘	✓