Psychiatric symptoms. Psychopathology. International Classification of Psychiatric disorders. DSM-5. Schizophrenia spectrum and other psychotic disorders. Bipolar and related disorders. Depressive disorders. Anxiety disorders. Obsessive-compulsive and related disorders. Trauma- and stressor-related disorders. Substance-related and addictive disorders. .Differential diagnosis. Neurotransmission and psychopharmacology. Anxiolytic drugs, antipsychotics, antidepressants, mood stabilizers.