Now I have comprehensive information from both the Kaplan & Sadock's Comprehensive Textbook of Psychiatry and multiple clinical references. Let me compile the complete, organized answer.
Drugs That Influence Psychiatric Function
This covers two broad categories: (1) Primary Psychotropic Drugs - those developed specifically for psychiatric indications, and (2) Non-Psychiatric Drugs - those primarily used for other conditions but with significant psychiatric effects (either therapeutic or adverse).
PART 1: PRIMARY PSYCHOTROPIC DRUGS (Psychiatric Drugs)
1. Antidepressants
Tricyclic Antidepressants (TCAs)
| Drug | Key Notes |
|---|
| Amitriptyline | Strong anticholinergic, also used for neuropathic pain, urticaria |
| Imipramine | Classic TCA, also used for enuresis |
| Clomipramine | Most serotonergic TCA; first-line for OCD |
| Nortriptyline | Better tolerated than amitriptyline |
| Desipramine | Most noradrenergic TCA |
| Doxepin | Also used for insomnia (low dose) and pruritus |
| Trimipramine | Sedating TCA |
| Protriptyline | Stimulating TCA |
| Amoxapine | Antipsychotic + antidepressant properties (D2 blockade) |
| Maprotiline | Tetracyclic; NRI |
Monoamine Oxidase Inhibitors (MAOIs)
| Drug | Type |
|---|
| Phenelzine | Irreversible, non-selective |
| Tranylcypromine | Irreversible, non-selective |
| Isocarboxazid | Irreversible, non-selective |
| Selegiline (transdermal) | Selective MAO-B (oral); non-selective (transdermal/high dose) |
| Moclobemide | Reversible MAO-A inhibitor (RIMA) |
Selective Serotonin Reuptake Inhibitors (SSRIs)
| Drug | Approved/Notable Indications |
|---|
| Fluoxetine | Depression, OCD, panic disorder, bulimia, PMDD, PTSD |
| Sertraline | Depression, OCD, panic disorder, PTSD, social anxiety, PMDD |
| Paroxetine | Depression, OCD, panic disorder, social anxiety, GAD, PTSD, PMDD |
| Escitalopram | Depression, GAD |
| Citalopram | Depression |
| Fluvoxamine | OCD, social anxiety disorder |
Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs)
| Drug | Approved/Notable Indications |
|---|
| Venlafaxine | Depression, GAD, social anxiety, panic disorder, PTSD |
| Desvenlafaxine | Depression |
| Duloxetine | Depression, GAD, neuropathic pain, fibromyalgia, chronic musculoskeletal pain |
| Levomilnacipran | Depression |
| Milnacipran | Fibromyalgia (marketed as pain drug in the US) |
Atypical Antidepressants
| Drug | Mechanism | Notes |
|---|
| Bupropion | NDRI (NE + DA reuptake inhibitor) | Also used for smoking cessation |
| Mirtazapine | NaSSA (alpha-2 antagonist) | Sedating, promotes appetite |
| Trazodone | SARI | Mainly used for insomnia at low dose |
| Nefazodone | SARI | Risk of hepatotoxicity |
| Vilazodone | SSRI + 5-HT1A partial agonist | |
| Vortioxetine | Multimodal serotonergic | |
Novel/Emerging Antidepressants
| Drug | Mechanism |
|---|
| Esketamine (Spravato) | NMDA antagonist (intranasal) - treatment-resistant depression |
| Psilocybin | 5-HT2A/2C agonist - FDA Breakthrough Therapy designation (2019) for depression |
| Brexanolone (Zulresso) | GABA-A positive allosteric modulator - postpartum depression |
| Zuranolone | Neuroactive steroid GABA-A modulator |
| Gepirone | 5-HT1A partial agonist |
| Agomelatine | MT1/MT2 agonist + 5-HT2C antagonist |
2. Antipsychotics (Neuroleptics)
First-Generation (Typical) Antipsychotics
Phenothiazines:
| Drug | Potency |
|---|
| Chlorpromazine | Low potency |
| Thioridazine | Low potency |
| Mesoridazine | Low potency |
| Trifluoperazine | High potency |
| Perphenazine | Mid potency |
| Fluphenazine | High potency (also depot) |
| Prochlorperazine | Also used as antiemetic |
Butyrophenones:
| Drug | Notes |
|---|
| Haloperidol | High potency; also available as long-acting injectable (LAI) |
| Droperidol | Also used in anesthesia as antiemetic |
Others:
| Drug | Class |
|---|
| Thiothixene | Thioxanthene |
| Loxapine | Dibenzoxazepine |
| Pimozide | Diphenylbutylpiperidine; also used for Tourette's |
| Molindone | Dihydroindolone |
Second-Generation (Atypical) Antipsychotics
| Drug | Notable Features |
|---|
| Clozapine | Gold standard for treatment-resistant schizophrenia; agranulocytosis risk; requires monitoring |
| Olanzapine | High metabolic risk; also used for bipolar mania/depression |
| Risperidone | Also depot (Risperdal Consta); children + adolescents |
| Paliperidone | Active metabolite of risperidone; monthly + 3-monthly LAI available |
| Quetiapine | Also used for bipolar depression; sedating |
| Aripiprazole | D2 partial agonist; also used for bipolar, MDD augmentation, irritability in autism |
| Brexpiprazole | D2 partial agonist; also MDD augmentation |
| Cariprazine | D2/D3 partial agonist; also bipolar depression |
| Ziprasidone | Least metabolic risk |
| Asenapine | Sublingual formulation; bipolar mania |
| Iloperidone | Requires titration |
| Lurasidone | Bipolar depression |
| Lumateperone | Depression in bipolar I/II |
| Pimavanserin | 5-HT2A inverse agonist; Parkinson's disease psychosis |
Long-Acting Injectable (LAI) Antipsychotics:
Haloperidol decanoate, Fluphenazine decanoate, Risperidone microspheres, Paliperidone palmitate (monthly, 3-monthly, 6-monthly), Aripiprazole monohydrate/lauroxil, Olanzapine pamoate
3. Mood Stabilizers
| Drug | Primary Indication | Notes |
|---|
| Lithium | Bipolar disorder (gold standard) | Narrow therapeutic index; also reduces suicidality |
| Valproate (Valproic acid / Divalproex) | Bipolar mania, epilepsy | Teratogenic; weight gain |
| Carbamazepine | Bipolar mania, epilepsy, trigeminal neuralgia | CYP inducer |
| Oxcarbazepine | Bipolar mania (off-label), epilepsy | Safer than carbamazepine |
| Lamotrigine | Bipolar depression (maintenance) | Rash/Stevens-Johnson risk |
| Topiramate | Bipolar (off-label), migraine, obesity | Cognitive side effects |
| Gabapentin | Anxiety, pain, bipolar (adjunct, off-label) | Not a true mood stabilizer |
| Pregabalin | GAD (Europe), pain, fibromyalgia | |
4. Anxiolytics / Sedative-Hypnotics
Benzodiazepines
Short-acting: Triazolam, Midazolam, Oxazepam, Temazepam
Medium-acting: Alprazolam, Lorazepam, Estazolam
Long-acting: Diazepam, Clonazepam, Chlordiazepoxide, Clorazepate, Flurazepam
Non-Benzodiazepine Hypnotics (Z-drugs)
| Drug |
|---|
| Zolpidem |
| Zaleplon |
| Eszopiclone |
Azapirones
| Drug | Indication |
|---|
| Buspirone | GAD (non-sedating, non-addictive 5-HT1A partial agonist) |
Melatonin Receptor Agonists
| Drug | Indication |
|---|
| Ramelteon | Insomnia (sleep onset) |
| Tasimelteon | Non-24-hour sleep-wake disorder |
Orexin Receptor Antagonists
| Drug | Indication |
|---|
| Suvorexant | Insomnia |
| Lemborexant | Insomnia |
| Daridorexant | Insomnia |
Antihistamines (Sedating)
| Drug | Use |
|---|
| Hydroxyzine | Anxiety, sedation |
| Diphenhydramine | Sleep aid |
| Doxylamine | OTC sleep aid |
5. Psychostimulants / ADHD Drugs
Amphetamines
| Drug |
|---|
| Amphetamine (mixed salts - Adderall) |
| Dextroamphetamine (Dexedrine) |
| Lisdexamfetamine (Vyvanse) |
| Methamphetamine (Desoxyn - rarely used) |
Methylphenidate-Class
| Drug |
|---|
| Methylphenidate (Ritalin, Concerta) |
| Dexmethylphenidate (Focalin) |
Non-Stimulant ADHD Drugs
| Drug | Mechanism |
|---|
| Atomoxetine | NRI (non-stimulant) |
| Viloxazine (Qelbree) | NRI |
| Clonidine (Kapvay) | Alpha-2 agonist |
| Guanfacine (Intuniv) | Alpha-2A agonist |
Wakefulness-Promoting
| Drug | Indication |
|---|
| Modafinil | Narcolepsy, shift work sleep disorder, obstructive sleep apnea |
| Armodafinil | Narcolepsy, shift work |
| Solriamfetol | Narcolepsy, OSA |
| Pitolisant | Narcolepsy (histamine H3 inverse agonist) |
6. Drugs for Dementia / Cognitive Disorders
| Drug | Mechanism | Indication |
|---|
| Donepezil | AChE inhibitor | Alzheimer's (all stages) |
| Rivastigmine | AChE + BuChE inhibitor | Alzheimer's, Parkinson's dementia |
| Galantamine | AChE inhibitor + nAChR modulator | Alzheimer's |
| Memantine | NMDA antagonist | Moderate-severe Alzheimer's |
| Lecanemab (Leqembi) | Anti-amyloid monoclonal antibody | Early Alzheimer's |
| Donanemab | Anti-amyloid monoclonal antibody | Early Alzheimer's |
| Aducanumab | Anti-amyloid monoclonal antibody | Alzheimer's |
7. Drugs for Substance Use Disorders
| Drug | Indication | Mechanism |
|---|
| Naltrexone | Alcohol use disorder, opioid use disorder | Opioid receptor antagonist |
| Naloxone | Opioid overdose reversal | Opioid receptor antagonist |
| Buprenorphine | Opioid use disorder | Partial mu-opioid agonist |
| Methadone | Opioid use disorder, pain | Full mu-opioid agonist |
| Disulfiram | Alcohol use disorder | Aldehyde dehydrogenase inhibitor |
| Acamprosate | Alcohol use disorder | NMDA modulator / GABA-A agonist |
| Varenicline (Chantix) | Smoking cessation | Partial alpha-4-beta-2 nAChR agonist |
| Bupropion | Smoking cessation | NDRI |
| Nicotine replacement | Smoking cessation | NRT |
| Lofexidine | Opioid withdrawal (non-opioid) | Alpha-2 agonist |
8. Other Psychiatric Drugs
| Drug | Indication |
|---|
| N-acetylcysteine (NAC) | OCD, substance use, trichotillomania (off-label) |
| Cyproheptadine | Serotonin syndrome, appetite stimulation |
| Propranolol | Performance anxiety, akathisia |
| Benztropine / Trihexyphenidyl | Antipsychotic-induced EPS |
| Amantadine | Antipsychotic-induced EPS |
PART 2: NON-PSYCHIATRIC DRUGS WITH SIGNIFICANT PSYCHIATRIC EFFECTS
These drugs are primarily prescribed for non-psychiatric conditions but can cause or be used for psychiatric symptoms.
A. Non-Psychiatric Drugs Used BENEFICIALLY in Psychiatry
| Drug | Primary Class | Psychiatric Use |
|---|
| Clonidine | Antihypertensive (alpha-2 agonist) | ADHD, PTSD nightmares, opioid withdrawal, Tourette's |
| Propranolol | Beta-blocker | Performance anxiety, PTSD (acute), akathisia, aggression |
| Verapamil | Calcium channel blocker | Bipolar disorder (adjunct) |
| Pregabalin | Anticonvulsant/pain | GAD (licensed in Europe), fibromyalgia-related anxiety |
| Gabapentin | Anticonvulsant/pain | Anxiety (off-label), bipolar adjunct, alcohol withdrawal |
| Ketamine (IV/IM) | Anesthetic | Treatment-resistant depression, suicidality |
| Lithium | (also renal/endocrine concern) | Bipolar (reduces suicide by ~5-fold) |
| Thyroid hormones (T3/T4) | Endocrine | Augmentation of antidepressants in depression |
| Minocycline | Antibiotic | Schizophrenia adjunct, depression (anti-inflammatory) |
| Rifampicin | Antibiotic | Depression (serotonergic mechanisms, investigational) |
| NSAIDs (e.g., aspirin, celecoxib) | Anti-inflammatory | Depression augmentation, schizophrenia adjunct (investigational) |
| Bumetanide | Loop diuretic | Autism spectrum disorder, schizophrenia (investigational - NKCC1 inhibitor) |
| Pramipexole | Antiparkinsonian (D2/D3 agonist) | Bipolar depression (third-line adjunct) |
| Hydroxyzine | Antihistamine | Anxiety (licensed in many countries for GAD) |
| Statins (simvastatin, etc.) | Lipid-lowering | Schizophrenia adjunct (anti-inflammatory, investigational) |
| S-Adenosyl-L-Methionine (SAMe) | OTC supplement | Depression (adjunct) |
| Omega-3 fatty acids (EPA) | Nutritional supplement | Depression augmentation |
| N-Acetylcysteine | OTC supplement | OCD, addictions, schizophrenia (oxidative stress pathway) |
B. Non-Psychiatric Drugs That Cause ADVERSE Psychiatric Effects
Cardiovascular/Antihypertensives
| Drug | Psychiatric Effect |
|---|
| Digoxin | Confusion, delirium, hallucinations |
| Beta-blockers (propranolol, metoprolol) | Depression, fatigue, nightmares, sexual dysfunction |
| Calcium channel blockers (diltiazem, verapamil) | Depression |
| Methyldopa | Depression, sedation |
| Reserpine | Depression (depletes monoamines - historical model of depression) |
| Clonidine (high dose or withdrawal) | Rebound anxiety, agitation |
| Antiarrhythmics (lidocaine, mexiletine) | Confusion, psychosis |
| Procainamide, quinidine | Delirium, psychosis |
Corticosteroids / Hormones
| Drug | Psychiatric Effect |
|---|
| Prednisone / Dexamethasone | Mania, psychosis ("steroid psychosis"), depression, insomnia, cognitive impairment |
| Anabolic steroids | Aggression ("roid rage"), depression on withdrawal |
| Estrogen / oral contraceptives | Depression, mood changes |
| Progesterone | Depression, irritability |
| Levothyroxine (excess) | Anxiety, irritability, mania-like |
| Corticotropin (ACTH) | Mood changes, psychosis |
Neurological / Anti-Parkinsonian
| Drug | Psychiatric Effect |
|---|
| Levodopa/Carbidopa | Hallucinations, psychosis, impulse control disorders, hypomania |
| Dopamine agonists (pramipexole, ropinirole) | Impulse control disorders (gambling, hypersexuality), psychosis |
| Amantadine | Confusion, hallucinations, psychosis |
| Anticholinergics (benztropine, trihexyphenidyl) | Confusion, delirium, hallucinations |
Anti-Epileptics (when adverse)
| Drug | Psychiatric Effect |
|---|
| Levetiracetam | Irritability, aggression, depression (common) |
| Topiramate | Cognitive slowing, depression, psychosis |
| Vigabatrin | Psychosis, depression |
| Phenobarbital | Sedation, depression, behavioral problems (children) |
| Phenytoin | Cognitive impairment, behavioral changes |
| Zonisamide | Psychosis, cognitive effects |
Antimicrobials / Antivirals
| Drug | Psychiatric Effect |
|---|
| Fluoroquinolones (ciprofloxacin, levofloxacin) | Anxiety, hallucinations, delirium, mania (in 0.9-11% of patients) |
| Isoniazid (INH) | Depression, psychosis (common; reduces pyridoxine) |
| Efavirenz (antiretroviral) | Vivid dreams, depression, psychosis, dissociation |
| Interferon-alpha | Severe depression, suicidality, psychosis |
| Mefloquine (antimalarial) | Psychosis, nightmares, depression |
| Chloroquine | Psychosis, mania |
| Clarithromycin | Mania, psychosis (rare) |
| Metronidazole | Confusion, psychosis (rare) |
| Aminoglycosides (gentamicin) | Confusion, acute psychosis (rare) |
Gastrointestinal Drugs
| Drug | Psychiatric Effect |
|---|
| Metoclopramide | Depression, tardive dyskinesia (chronic use) |
| H2 blockers (cimetidine, ranitidine) | Confusion, delirium, hallucinations (especially elderly/renally impaired) |
| Proton pump inhibitors | Neuropsychiatric events in vulnerable patients |
Anti-Cancer / Immunosuppressant Drugs
| Drug | Psychiatric Effect |
|---|
| Procarbazine | MAOI-like activity; depression, psychosis |
| Vincristine | Depression |
| Tamoxifen | Depression, mood changes |
| Medroxyprogesterone | Depression |
| Interferon-beta | Depression, fatigue |
| Cyclosporine | Anxiety, confusion, hallucinations |
| Tacrolimus (FK506) | Anxiety, confusion, delirium |
Analgesics
| Drug | Psychiatric Effect |
|---|
| Opioids (morphine, oxycodone) | Euphoria, dysphoria, confusion, delirium |
| Tramadol | Serotonin syndrome risk, mania (rare), seizures |
| NSAIDs | Anxiety, psychosis (rare) |
| Indomethacin | Depression, psychosis |
Respiratory / Bronchodilators
| Drug | Psychiatric Effect |
|---|
| Beta-2 agonists (salbutamol, salmeterol) | Anxiety, agitation, tremor |
| Theophylline | Anxiety, insomnia, agitation, psychosis at toxic levels |
| Corticosteroids (inhaled high dose) | Mood changes, behavioral effects (children) |
| OTC antihistamine-decongestant combos | Psychosis, delirium |
Muscle Relaxants
| Drug | Psychiatric Effect |
|---|
| Baclofen | Confusion, hallucinations, psychosis (especially on abrupt withdrawal) |
| Cyclobenzaprine | Confusion, disorientation |
| Carisoprodol | CNS depression, dependence |
Recreational / OTC Substances
| Drug | Psychiatric Effect |
|---|
| Sympathomimetics (pseudoephedrine in cold meds) | Psychosis, anxiety, agitation |
| Diphenhydramine (OTC sleep) | Delirium (anticholinergic), paradoxical excitation |
| Dextromethorphan (DXM) | Dissociative psychosis at high doses |
Key Concept: Neuroscience-Based Nomenclature (NbN)
The traditional classification of psychotropic drugs by indication is being superseded by mechanism-based classification. As noted in Kaplan & Sadock's Comprehensive Textbook of Psychiatry, drugs like clonidine, propranolol, verapamil, and pregabalin - not officially "psychotropic" - are widely used to manage psychiatric disorders, and newer antidepressants have gained approval across panic disorder, GAD, OCD, PTSD, and chronic pain. The movement toward NbN (pharmacological target + mode of action) better reflects how these drugs actually work.
Sources:
- Kaplan & Sadock's Comprehensive Textbook of Psychiatry (10th ed.)
- Stahl's Essential Psychopharmacology
- The Maudsley Prescribing Guidelines in Psychiatry, 15th ed.
- Treating psychiatric symptoms with non-psychotropic medications (PMC6787535)
- Adverse psychiatric effects of non-psychotropic medications (BJPsych Advances)
- Nonpsychotropic Medication-Induced Psychosis (US Pharmacist)
