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 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 well known mood stabilizers. Medications used for epilepsy mainly Sodium Valproate and Carbamazepine are some other mood stabilizers. Recently 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 in long term. These are also used to decrease agitation in other major psychiatric illnesses. Propranolol is medicine used to treat high blood pressure is used to treat some of 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.
Post Traumatic Stress Disorder (PTSD)
PTSD is a type of anxiety disorder which occurs after a traumatic event.Obsessive Compulsive Disorder
It is a type of neurotic illness in which the patient gets repeated unwanted thoughts inspite of the fact that he knows that those thoughts are senseless and tries to resist those. They are often accompanied by compulsive actions. For example getting repeated thoughts that ones body are contaminated and as a result repeatedly washing.