1. What are the main classes of antidepressants and how do they differ in their mechanism of action? Answer: The main classes of antidepressants are selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs), and atypical antidepressants. They differ in their mechanism of action by affecting the availability and metabolism of different neurotransmitters, such as serotonin, norepinephrine, dopamine, and histamine, in the synaptic cleft. 2. What are the common side effects and contraindications of antipsychotics? Answer: The common side effects of antipsychotics include extrapyramidal symptoms (EPS), such as dystonia, akathisia, parkinsonism, and tardive dyskinesia; metabolic syndrome, such as weight gain, diabetes, dyslipidemia, and cardiovascular dis ease; neuroleptic malignant syndrome (NMS), a life-threatening condition characterized by fever, muscle rigidity, altered mental status, and autonomic instability; and anticholinergic effects, such as dry mouth, blurred vision, constipation, urinary retention, and c ognitive impairment. The contraindications of antipsychotics include hypersensitivity to the drug or its components, severe central nervous system depression, blood dyscrasias, liver or renal impairment, narrow-angle glaucoma, and cardiac arrhythmias. 3. What are the indications and precautions of lithium therapy for bipolar disorder? Answer: Lithium is a mood stabilizer that is indicated for the treatment of acute mania and maintenance therapy for bipolar disorder. Lithium has a narrow therapeutic window and requires regular monitoring of serum levels, renal function, thyroid function, and electrolytes. Lithium can cause toxicity if the serum level exceeds 1.5 mEq/L, which can manifest as nausea, vomiting, diarrhea, tremor, ataxia, confusion, seizures, coma, and death. Lithium therapy should be used with caution in patients with renal impairment, dehydration, hyponatremia, cardiovascular disease, thyroid disease, pregnancy, and breastfeeding. 4. What are the advantages and disadvantages of benzodiazepines for anxiety disorders? Answer: Benzodiazepines are sedative-hypnotic drugs that enhance the activity of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter in the brain. Benzodiazepines have advantages such as rapid onset of action, high efficacy, low toxicity, and wide therapeutic index. However, benzodiazepines also have disadvantages such as dependence potential, withdrawal syndrome, tolerance development, cognitive impairment, respiratory depression, and drug interactions. 5. What are the principles and goals of pharmacogenomics in psychopharmacology? Answer: Pharmacogenomics is the study of how genetic variations affect the response to drugs. The principles of pharmacogenomics include identifying genetic markers that predict drug efficacy and toxicity, tailoring drug selection and dosage to individual genetic profiles, and optimizing drug therapy outcomes. The goals of pharmacogenomics in psychopharmacology include improving treatment response, reducing adverse effects, enhancing patient adherence, and increasing cost-effectiveness. 6. What are the clinical features and pharmacological management of attention-deficit/hyperactivity disorder (ADHD)? Answer: ADHD is a neurodevelopmental disorder characterized by persistent patterns of inattention, hyperactivity, and impulsivity that interfere with functioning or development. The pharmacological management of ADHD involves stimulants, such as methylphenidate and amphetamine, and non-stimulants, such as atomoxetine