| 5HT3 | 5-hydroxytryptamine 3 |
| 22q11.2DS | 22q11.2 deletion syndrome |
| %w/v | percentage weight per volume |
| AACAP | American Academy of Child and Adolescent Psychiatry |
| ACE | angiotensin-converting enzyme |
| Ach | acetylcholine |
| AChE | acetylcholinesterase |
| AChE-I | acetylcholinesterase inhibitors |
| ACOG | American College of Obstetricians and Gynecologists |
| AD | Alzheimer's disease |
| ADAPT | Adolescent Depression Antidepressants and Psychotherapy Trial |
| ADAS-cog | Alzheimer's Disease Assessment Scale - cognitive subscale |
| ADH | alcohol dehydrogenase |
| ADHD | attention deficit hyperactivity disorder |
| ADIS | Anxiety Disorders Interview Schedule |
| ADL | activities of daily living |
| ADR | adverse drug reactions |
| AEC | Anticholinergic Effect on Cognition Scale |
| AF | atrial fibrillation |
| AIDS | acquired immune deficiency syndrome |
| ALAI | aripiprazole long-acting injection |
| ALP | alkaline phosphate |
| ALT | alanine aminotransferase |
| AMPA | alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid |
| AN | anorexia nervosa |
| ANC | absolute neutrophil count |
| ANI | asymptomatic neurocognitive impairment |
| APP | amyloid precursor protein |
| ARIA | amyloid-related imaging abnormality |
| ART | antiretroviral therapy |
| ASD | autism spectrum disorder |
| AST | aspartate aminotransferase |
| ATPase | adenosine triphosphatase |
| AUD | alcohol use disorder |
| AUDIT | Alcohol Use Disorders Identification Test |
| Aβ | beta amyloid |
| BAC | blood alcohol concentration |
| BAP | British Association for Psychopharmacology |
| BBB | blood-brain barrier |
| bd | twice a day |
| BDD | body dysmorphic disorder |
| BDNF | brain-derived neurotrophic factor |
| BED | binge eating disorder |
| BEN | benign ethnic neutropenia |
| BMI | body mass index |
| BN | bulimia nervosa |
| BNF | British National Formulary |
| BP | blood pressure |
| BPD | Borderline personality disorder |
| BPSD | behavioural and psychological symptoms of dementia |
| BuChE | butyrylcholinesterase |
| CAMS | Childhood Anxiety Multimodal Study |
| CATIE | Clinical Antipsychosis Trials of Intervention Effectiveness |
| CBT | cognitive behavioural therapy |
| CDRS | Children's Depression Rating Scale |
| CDR-SB | Clinical Dementia Rating Scale - Sums of Boxes |
| CDRS-R | Children's Depression Rating Scale-Revised |
| CGAS | Children's Global Assessment Scale |
| CGI | Clinical Global Impression |
| CI | confidence interval |
| CIBIC-plus | Clinician's Interview-Based Impression of Change plus caregiver input |
| CIGH | clozapine-induced GI hypomotility |
| CIWA-Ar | Clinical Institute Withdrawal Assessment of Alcohol Scale Revised |
| CK | creatine kinase |
| CKD | chronic kidney disease |
| CKD-EPI | Chronic Kidney Disease Epidemiology Collaboration |
| CNS | central nervous system |
| COCP | combined oral contraceptive pill |
| COMT | catechol-O-methyltransferase |
| COPD | chronic obstructive pulmonary disease |
| COWS | Clinical Opiate Withdrawal Scale |
| CQC | Care Quality Commission |
| CrCl | creatinine clearance |
| CRLTA | clozapine-related life-threatening agranulocytosis |
| CRP | C-reactive protein |
| CTO | Community Treatment Order |
| CUtLASS | Cost Utility of the Latest Antipsychotic Drugs in Schizophrenia Study |
| CVD | cardiovascular disease |
| CY-BOCS | Children's Yale-Brown Obsessive Compulsive Scale |
| CYP | cytochrome P450 |
| DAI | Drug Attitude Inventory |
| DBM | dibenzoylmethane |
| DBT | dialectical behaviour therapy |
| DEXA | dual-energy x-ray absorptiometry |
| DHA | docosahexaenoic acid |
| DHEA | dehydroepiandrosterone |
| DIVA-5 | Diagnostic Interview for ADHD in Adults |
| DLB | dementia with Lewy bodies |
| DMDD | disruptive mood dysregulation disorder |
| DMq | dextromethorphan and low-dose quinidine |
| DOACs | direct-acting oral anticoagulants |
| DoLS | Deprivation of Liberty Safeguards |
| DSM-5 | Diagnostic and Statistical Manual of Mental Disorders, 5th edition |
| DVLA | Driver and Vehicle Licensing Agency |
| ECG | electrocardiogram |
| ECT | electroconvulsive therapy |
| EEG | electroencephalogram |
| eGFR | estimated glomerular filtration rate |
| EMDR | eye movement desensitisation and reprocessing |
| EOSS | early-onset schizophrenia spectrum |
| EPA | eicosapentaenoic acid |
| EPS | extrapyramidal symptoms |
| EPSE | extrapyramidal side effect |
| ER | extended release |
| ERK | extracellular signal-regulated kinase |
| ES | effect size |
| EU | European Union |
| FBC | full blood count |
| FDA | Food and Drug Administration |
| FGA | first-generation antipsychotic |
| FPG | fasting plasma glucose |
| FRAMES | feedback, responsibility,principlesadvice, menu, empathy, self-efficacy |
| FSH | follicle-stimulating hormone |
| FTI | Fatal Toxicity Index |
| GABA | gamma-aminobutyric acid |
| GAD | generalised anxiety disorder |
| GASS | Glasgow Antipsychotic Side-effect Scale |
| GBL | gamma-butyrolactone |
| G-CSF | granulocyte colony-stimulating factor |
| GERD | gastro-esophageal reflux disease |
| GFR | glomerular filtration rate |
| GGT | gamma-glutamyl transferase |
| GHB | gamma-hydroxybutyrate |
| GHB/GBL | gamma-hydroxybutyrate/gamma-butyrolactone |
| GI | gastrointestinal |
| GLP-1 | glucagon-like peptide-1 |
| GP | general practitioner |
| GRDS | gastric reduction duodenal switch |
| GSM | genitourinary symptoms of menopause |
| HAD | HIV-associated dementia |
| HAM-D | Hamilton Depression Rating Scale |
| HAND | HIV-assocated neurocognitive disorders |
| HbA1c | glycated haemoglobin |
| HCl | hydrogen chloride |
| HD | Huntington's disease |
| HDL | high-density lipoprotein |
| hERG | human ether-a-go-go-related gene |
| HIV | human immunodeficiency virus |
| HLA | human lymphocyte antigen |
| HPA | hypothalamic-pituitary-adrenal |
| HR | hazard ratio |
| HRT | hormone replacement therapy |
| IADL | instrumental activities of daily living |
| ICD-10 | International Classification of Diseases 10 |
| ICH | intracranial/intracerebral haemorrhage |
| IGSLI | International Study Group on Lithium |
| IHD | ischaemic heart disease |
| IM | intramuscular |
| INR | international normalised ratio |
| IR | immediate release |
| ISBD | International Society for Bipolar Disorders |
| ISTSS | International Society for Traumatic Stress Studies |
| IV | intravenous |
| Kiddie-SADS | Kiddie-Schedule for Affective Disorders and Schizophrenia |
| LAI | long-acting injection |
| LC-MS | liquid chromatography and mass spectrometry |
| LD | learning disabilities |
| LDL | low-density lipoprotein |
| LFT | liver function test |
| LGIB | lower gastrointestinal bleeding |
| LMP | last menstrual period |
| MADRS | Montgomery-Asberg Depression Rating Scale |
| MAO | monoamine oxidase |
| MAOI | monoamine oxidase inhibitor |
| MARS | Medication Adherence Rating Scale |
| MASC | Multidimensional Anxiety Scale for Children |
| MCA | Mental Capacity Act |
| MCI | mild cognitive impairment |
| MDD | major depressive disorder |
| MDMA | 3,4-methylenedioxymethamphetamine |
| MDRD | Modification of Diet in Renal Disease |
| MDT | multidisciplinary team |
| MFQ | Mood and Feelings Questionnaire |
| MHA | Mental Health Act |
| MHRA | Medicines and Healthcare products Regulatory Authority |
| MI | myocardial infarction |
| MMSE | Mini Mental State Examination |
| MND | mild neurocognitive disorder |
| MoCA | Montreal Cognitive Assessment |
| MR | modified release |
| MS | mood stabilisers/multiple sclerosis |
| MSM | men who have sex with men |
| NAPLS | North American Prodromal Longitudinal Studies |
| NaSSA | noradrenergic and specific serotonergic antidepressant |
| NbN | neuroscience-based nomenclature |
| NEET | not in education, employment or education |
| NICE | National Institute for Health and Care Excellence |
| NIMH | National Institute of Mental Health |
| NMDA | N-methyl-D-aspartate |
| NMDAR | N-methyl-D-aspartate receptor |
| NMS | neuroleptic malignant syndrome |
| NNH | number needed to harm |
| NNT | number needed to treat |
| NPIS | National Poisons Information Service |
| NPS | new psychoactive substances |
| NPV | negative predictive value |
| NRT | nicotine replacement therapy |
| NSAID | non-steroidal anti-inflammatory drug |
| OCD | obsessive compulsive disorder |
| od | once daily |
| OGTT | oral glucose tolerance test |
| on | at night |
| OOWS | Objective Opiate Withdrawal Scale |
| OR | odds ratio |
| OST | opioid substitution treatment |
| PAIN | Peri-operative Pain and Addiction Interdisciplinary Network |
| PANDAS | paediatric autoimmune neuropsychiatric disorder associated with Streptococcus |
| PANS | paediatric acute-onset neuropsychiatric syndrome |
| PANSS | Positive and Negative Syndrome Scale |
| PAWS | post-acute withdrawal syndrome |
| PBA | pseudobulbar affect |
| PD | Parkinson's disease |
| PDSS | post-injection delirium sedation syndrome |
| PE | pulmonary embolism |
| PET | positron emission tomography |
| PG | propylene glycol |
| P-gp | P-glycoprotein |
| PHQ-9 | Patient Health Questionnaire-9 |
| PLWH | people living with HIV |
| PMDD | premenstrual dysphoric disorder |
| PMR | postmortem redistribution |
| PMS | premenstrual syndrome |
| po | by mouth |
| POI | premature ovarian insufficiency |
| PORT | Program of Rehabilitation and Therapy |
| PP1M | paliperidone long-acting injection 1-monthly |
| PP3M | paliperidone long-acting injection 3-monthly |
| PPH | postpartum haemorrhage |
| PPI | proton pump inhibitor |
| PPV | positive predictive value |
| prn | as required |
| PSSD | post-SSRI sexual dysfunction |
| PT | prothrombin time |
| PTSD | post-traumatic stress disorder |
| PUFA | polyunsaturated fatty acid |
| PWE | people with epilepsy |
| RANZCP | Royal Australian and New Zealand College of Psychiatrists |
| RC | Responsible Clinician |
| RCADS | Revised Children's Anxiety and Depression Scale |
| RCT | randomised controlled trial |
| REM | rapid eye movement |
| RID | relative infant dose |
| RIMA | reversible inhibitor of monoamine oxidase A |
| RLAI | risperidone long-acting injection |
| ROMI | Rating of Medication Influences |
| RR | respiratory rate/risk ratio |
| RRBI | restricted repetitive behaviours and interests |
| RT | rapid tranquillisation |
| RTA | road traffic accident |
| rTMS | repetitive transcranial magnetic stimulation |
| RUPP | Research Units on Paediatric Psychopharmacology |
| RYGB | Roux-en-Y gastric bypass |
| SADQ | Severity of Alcohol Dependence Questionnaire |
| SAWS | Short Alcohol Withdrawal Scale |
| SC | subcutaneous |
| SCARED | Screen for Child Anxiety and Related Emotional Disorders |
| SCRA | synthetic cannabinoid receptor agonist |
| SD | sexual dysfunction |
| SERM | selective oestrogen receptor modulators |
| SERT | serotonin receptor |
| SGA | second-generation antipsychotic |
| SIADH | syndrome of inappropriate secretion of antidiuretic hormone |
| SIB | Severe Impairment Battery |
| SJW | St John's wort |
| SNRI | serotonin-noradrenaline reuptake inhibitor |
| SOAD | Second Opinion Appointed Doctor |
| SPC | Summary of Product Characteristics |
| SROM | slow-release oral morphine |
| SSRI | selective serotonin reuptake inhibitor |
| STAR*D | Sequenced Treatment Alternatives to Relieve Depression |
| STOP-PD II | Study of the Pharmacotherapy of Psychotic Depression II |
| SUD | stimulant use disorder |
| TADS | Treatment of Adolescents with Depression Study |
| TCA | tricyclic antidepressant |
| TD | tardive dyskinesia |
| tDCS | transcranial direct current stimulation |
| TDM | therapeutic drug monitoring |
| TdP | torsades de pointes |
| tds | three times a day |
| TF-CBT | trauma-focused cognitive behavioural therapy |
| TFT | thyroid function test |
| TIA | transient ischaemic attack |
| tMS | transcranial magnetic stimulation |
| TORDIA | Treatment of Resistant Depression in Adolescents |
| TRBD | treatment-resistant bipolar disorder |
| TRD | treatment-resistant depression |
| TREC | Tranquilização Rápida-Ensaio Clínico [Rapid Tranquillisation Clinical Trial] |
| TRS | treatment-resistant schizophrenia |
| TS | Tourette syndrome |
| U&Es | urea and electrolytes |
| UDP | uridine diphosphate |
| UGT | UDP-glucuronosyltransferase |
| UGIB | upper gastrointestinal bleeding |
| UGT | UDP-glucuronosyltransferase |
| UKTIS | UK Teratology Information Service |
| VaD | vascular dementia |
| VG | vegetable glycerine |
| VHR | Vienna High Risk |
| VMAT-2 | vesicular monoamine transporter 2 |
| VNS | vagal nerve stimulation |
| VTE | venous thromboembolism |
| WBC | white blood cell |
| WCC | white cell count |
| WHO | World Health Organization |
| YMRS | Young Mania Rating Scale |
| ZA | zuclopenthixol acetate |