Psychopharmacology aims to investigate the interactions between drugs and the brain, leading to a better understanding of how drugs affect behavior and mental processes.

Antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), work by increasing the levels of serotonin in the brain, which is associated with mood regulation.

Antipsychotics primarily work by blocking dopamine receptors in the brain, reducing dopaminergic activity, which is thought to be involved in the symptoms of schizophrenia and other psychotic disorders.

Benzodiazepines, such as diazepam and alprazolam, are commonly prescribed for anxiety disorders due to their rapid anxiolytic effects and relatively low risk of serious side effects.

Psychostimulants, such as amphetamines and methylphenidate, work primarily by increasing the levels of dopamine and norepinephrine in the brain, leading to increased alertness, focus, and energy.

Methadone and buprenorphine are opioid agonists that are used in opioid addiction treatment to reduce withdrawal symptoms and cravings, while naltrexone is an opioid antagonist that blocks the effects of opioids.

Anticonvulsants, such as phenytoin and valproate, primarily work by blocking sodium channels in the brain, reducing neuronal excitability and preventing seizures.

Anticholinergic drugs, such as atropine and scopolamine, work by blocking the action of acetylcholine at muscarinic receptors, leading to reduced parasympathetic activity.

Hallucinogens, such as LSD and psilocybin, primarily work by activating serotonin receptors, particularly the 5-HT2A receptor, leading to altered perceptions, hallucinations, and changes in mood and consciousness.

Levodopa and dopamine agonists are commonly used in Parkinson's disease treatment to increase dopamine levels in the brain, improving motor symptoms.

Mood stabilizers, such as lithium and valproate, work primarily by stabilizing dopamine levels in the brain, preventing extreme mood swings and reducing the risk of manic or depressive episodes.

Stimulants, such as methylphenidate and amphetamine, are commonly used to treat ADHD due to their ability to improve attention, focus, and behavior in individuals with the disorder.

Atypical antipsychotics, such as clozapine and olanzapine, work primarily by blocking both dopamine and serotonin receptors, providing a broader spectrum of activity compared to typical antipsychotics.

Drugs used to treat Alzheimer's disease, such as cholinesterase inhibitors and memantine, primarily target the cholinergic system, aiming to increase acetylcholine levels or block its breakdown in the brain.

NSAIDs, such as ibuprofen and naproxen, work primarily by inhibiting cyclooxygenase enzymes, reducing the production of prostaglandins, which are involved in pain, inflammation, and fever.