The medicines used to treat mental disorders can be divided in following groups:

Antidepressants

These are medicines used to treat depression. However they are also used to treat anxiety disorders including OCD (Obsessive Compulsive Disorders), Panic Disorder, certain Phobias and Post Traumatic Stress Disorder. Some antidepressants can also play a  part in treatment of Bulimia Nervosa.

Antipsychotics

They are used to treat various psychotic disorders for example Schizophrenia, Scizoaffective Disorder, Delusional Disorder, Puerperal Psychosis etc. The older antipsychotics e.g. Chlorpromazine, Haloperidol, Trifluperazine (Stelazine), flupenthixol etc. have relatively more side effects than newer (also called Atypical Antipsychotics) e.g Olanzapine, Quietiapine, Risperidone, Amisulpiride, Aripiprazole. Saying that Atypical Antipsychotics also have side effects ( there is no effective medicine free of side effects).

Mood Stabilizers

These are medicines used to treat and prevent episodes of Bipolar Affective Disorders. Lithium Carbonate is a well known mood stabilizer. Medications used for epilepsy mainly Sodium Valproate and Carbamazepine are some other mood stabilizers. Some of the Atypical Antipsychotics are licensed and used to treat mania.

Anxiolytics

Benzodiazepines for example Diazepam, Lorazepam are well known medications used for short term treatment of acute anxiety however these are addictive medications and should not be used long term. These are also used to decrease agitation in other major psychiatric illnesses. Propranolol is a medicine used to treat high blood pressure and is used to treat some of the physical symptoms of anxiety e.g. palpitation and tremors.

Hypnotics

These are medicines used for short term symptomatic treatment of insomnia. Zopiclone Zolpidem and Zoleplone are well known. Temazepam is often avoided due to its addictive potential and abuse.