Common Side Effects of Psychiatric Medications, Including Antipsychotics
Psychiatric medications, particularly antipsychotics, cause a wide range of adverse effects that span from minor tolerability issues to life-threatening complications, with specific side effect profiles varying dramatically between individual medications rather than fitting neatly into first- versus second-generation classifications 1.
Antipsychotic Side Effects by Category
Neurological Effects
Movement disorders represent the most characteristic neurological complications:
- Extrapyramidal symptoms (EPS): Parkinsonism, akathisia, and acute dystonias occur more commonly with traditional antipsychotics, though atypical agents (especially risperidone at higher doses) can also cause these 2
- Tardive dyskinesia (TD): Persistent involuntary movements that may not resolve even after medication discontinuation; requires monitoring with the Abnormal Involuntary Movement Scale every 3-6 months 2
- Tardive dystonia: Slow movements culminating in spasms along the body's long axis, often disabling and associated with TD 2
- Neuroleptic malignant syndrome (NMS): A potentially fatal complication that can occur with any antipsychotic 2
Critical caveat: While atypical antipsychotics theoretically carry lower risk for movement disorders, risperidone demonstrates the highest EPS risk among atypicals, and cases of NMS and TD have been reported in teenagers taking this medication 2.
Metabolic and Endocrine Effects
Weight gain stands as the most common significant problem with atypical antipsychotics and can be extreme 2:
- Highest risk agents: Clozapine and olanzapine 3, 4
- Associated complications: Type 2 diabetes mellitus, dyslipidemia, and metabolic syndrome 3, 5
- Hyperprolactinemia: Causes sexual dysfunction; highest risk with amisulpride and risperidone 4
Cardiovascular Effects
- Orthostatic hypotension: Common across antipsychotics 2
- QTc prolongation: Documented with atypical antipsychotics, particularly ziprasidone and sertindole; youth may be more susceptible to cardiac effects 2, 4
- Tachycardia: Especially with clozapine 2
- Increased risk: Cardiac arrhythmia and sudden cardiac death with all antipsychotics 3
Cognitive Effects
Traditional antipsychotics cause sedation, cognitive blunting, apathy, and memory deficits, particularly low-potency agents with greater anticholinergic activity 2. Conversely, atypical antipsychotics show benefits in fine motor function, memory, and executive function compared to traditional agents 2.
Hematological Effects
Clozapine-specific but possible with any antipsychotic:
- Agranulocytosis: Occurs in approximately 1% of clozapine patients and is potentially fatal; requires weekly blood monitoring for 6 months, then biweekly 2
- Seizures: Occur in approximately 3% of clozapine patients, risk increases with rapid dose escalation 2
- Leukocytopenia: Reported with risperidone and quetiapine in youth 2
Hepatic Effects
Atypical agents produce transient elevations in hepatic transaminase levels; liver enzyme abnormalities and fatty infiltrates have been documented in adolescents on risperidone, particularly associated with obesity 2.
Other Common Effects
Traditional antipsychotics:
- Sedation
- Sexual dysfunction
- Lowered seizure threshold
- Photosensitivity and cholestatic jaundice (phenothiazines)
- Lenticular stippling (thioridazine) 2
Clozapine-specific:
- Hypersalivation
- Fever
- Elevated liver enzymes 2
Atypical antipsychotics:
- Sedation, activation, and dizziness 2
- Cataracts (quetiapine in animal studies; FDA recommends baseline and 6-month eye exams) 2
Critical Clinical Implications
The evidence demonstrates that adverse effects reduce medication compliance, impair quality of life, cause stigma, and in extreme cases can be fatal 6. The variation in tolerability between specific medications means broad comparisons between "typical" versus "atypical" classes are largely meaningless—comparisons must be made between specific agents 4.
Monitoring requirements differ by agent: Clozapine demands extensive hematological surveillance with specific WBC and ANC thresholds for continuation or discontinuation 2. Baseline liver function testing with periodic monitoring is prudent for atypical agents 2.
Important principle: Adverse effects are dose-dependent and influenced by patient characteristics including age and gender 4. Youth may experience higher rates of side effects, including seizures and agranulocytosis with clozapine 2.