Background: Patient features, apart from the type of seizures/epilepsy, affect markedly antiepileptic drug (AED) choice and dosage. The present review focuses on gender, age and psychiatric comorbidities which play a leading role in influencing antiepileptic treatment.Methods: Reviews with large population of patients, controlled clinical trials, observational investigations, experimental studies and experimental reviews of experimental data, where appropriated, were analysed and illustrated to produce the most homogeneous indications possible. Different and also contradictory observations have been highlighted to stimulate a critical approach to specific aspects. Results: Women of childbearing age should avoid valproic (VPA), acid, since this drug doubles the risk of major malformations and causes in the exposed offspring reduced intellectual development and disorders of autistic spectrum. The drug is also associated with hormonal disorders, polycystic ovary and reduced fertility. Children treated with valproic acid or phenobarbital can exhibit hyperactivity, nervousness and attention disorders. As a consequence of increased drug elimination, younger children require higher doses as compared to adults and older patients. Elderly patients treated with phenobarbital may face the risk of cognitive disorders and/or falls resulting in bone fractures. Fractures are also facilitated by carbamazepine-induced osteoporosis. Psychiatric disorders are frequently associated with epilepsy and evidence has been gained that common pathological steps underlie these conditions. Depressed patients should avoid drugs like phenobarbital, topiramate, levetiracetam, zonisamide and perampanel since these drugs can induce mood disorders. Although not conclusive, literature data indicate that topiramate and levetiracetam and also tiagabine and vigabatrin, are associated with suicidal thought/behaviour. Conversely, lamotrigine, carbamazepine, VPA and oxcarbazepine exert beneficial effects on mood. Bupropion, clomipramine, amoxapine and maprotyline among antidepressants, and clozapine, olanzapine and quietapine among antipsychotics have been observed to lower seizure threshold. Serum AED concentration monitoring is of help in dosage adjustments, especially in very young children, in patients with cognitive decline and in patients with psychiatric comorbidities. Conclusions: A careful evaluation of the patient variables analysed in the present review is useful to personalize and optimize AED therapy.