Aripiprazole — Abilify — is the third-generation antipsychotic, distinguished from FGAs and SGAs by a fundamentally different mechanism: dopamine partial agonism. Instead of fully blocking D2 receptors, aripiprazole occupies them and provides roughly 30 percent of full activation. The clinical concept is "dopamine stabilizer" — provides signal where deficient, reduces signal where excessive.
- Class
- Third-generation antipsychotic / dopamine partial agonist
- Mechanism
- D2 partial agonist + 5-HT1A partial agonist + 5-HT2A antagonist. "Dopamine stabilizer" — provides dopamine signal where deficient (PFC), reduces signal where excessive (mesolimbic).
- Typical dose
- 10-30 mg/day (schizophrenia, bipolar); 2-15 mg (depression adjunct); LAI Maintena monthly 300-400 mg, Aristada monthly-q6wk
- Half-life
- ~75 hours (parent) — long; active metabolite ~94 hours
- FDA indications
- Schizophrenia, bipolar I, MDD adjunct, irritability in autism, Tourette syndrome
- Key adverse effects
- Akathisia (prominent — sometimes severe and limiting), insomnia, nausea, low weight gain, low metabolic effects, low prolactin (can lower prolactin), impulse control disorders (rare but emergent — gambling, hypersexuality)
Black box: Increased mortality in elderly patients with dementia-related psychosis
Distinctive partial agonist mechanism: dopamine "stabilizer" rather than blocker. Very favorable metabolic profile. Akathisia is the classic side effect — often severe enough to limit use. Impulse control disorders are rare but serious adverse effect; counsel patients to monitor and report.
In practice, this means aripiprazole behaves differently in different pathways. In the mesolimbic pathway where dopamine is excessive in psychosis, aripiprazole competes with endogenous dopamine and reduces signaling — the antipsychotic effect. In the PFC and other regions where dopamine signaling may be insufficient, aripiprazole provides partial signal where there was none — possibly explaining benefits on cognition and negative symptoms. In the tuberoinfundibular pathway, the partial agonism preserves enough dopamine signal to suppress prolactin — aripiprazole actually lowers prolactin, the opposite of most antipsychotics. This is why aripiprazole is sometimes used adjunctively to treat risperidone-induced hyperprolactinemia.
Aripiprazole is the prototype third-generation antipsychotic — a D2 partial agonist that stabilizes rather than simply blocks dopamine transmission.
Mechanism note: Aripiprazole's partial-agonist mechanism gives a low EPS, low prolactin, low metabolic profile — the trade-offs are akathisia and the under-recognized impulse-control disorder signal.
The metabolic profile is among the most favorable in the class. Minimal weight gain. Minimal lipid effects. Minimal glucose dysregulation. For patients with metabolic risk, aripiprazole is often a leading choice.
The counterweight is akathisia. Aripiprazole produces akathisia in a substantial portion of patients — sometimes severe, sometimes limiting. The inner restlessness is often misattributed to anxiety or worsening psychosis. Treatment: propranolol, benzodiazepine, dose reduction, or switch. The patient who experiences akathisia on aripiprazole may need brexpiprazole (closely related, less akathisia, more sedation/weight) or a different class entirely.
Impulse control disorders are a rare but emergent side effect — pathological gambling, hypersexuality, compulsive shopping. Same phenomenon seen with dopamine agonists in Parkinson's disease. Counsel patients at prescription and ask at follow-ups.
Indications are broad: schizophrenia, bipolar I, MDD adjunct, irritability in autism, Tourette syndrome. Aripiprazole has both oral and long-acting injectable formulations (Maintena monthly, Aristada with varying intervals). For metabolically vulnerable patients needing antipsychotic coverage, aripiprazole is often the right answer.