If you are claiming that your Thai wife is insane and this being the bases for the divorce then it is a long and costly process as your wife would need to be declared insane and an order made by the family courts in Thailand for a curator as well as an order for child custody. Speak to a divorce lawyer in Thailand about this before you embark on this process.
Starting the process will be a costly affair as an order needs to be made for maintenance for your Thai wife during the process. This is covered by the Thai Civil and Commercial Code being the made statue in Thailand for most laws. Note that in terms of Section 1464 an order can be made to maintain the household even before the divorce has been granted or your wife being declared insane. This maintenance order is not a permanent order only interim while the divorce proceeds.
Note that should the courts find your wife insane and she has no guardian appointed then they will granted the maintenance order and the declaration of insanity and dismiss the divorce application while a guardian is appointed. The maintenance order is based on the earnings of the two parties and it is normally proportional to their income abilities. For further reading on the issue see the relevant section on Thai divorce laws such as Section 1519.
Insanity is a grounds for divorce under Section 1516 (7) and you can search this website for more information with regards to the grounds for divorce in Thailand. Getting divorced is a complex matter in Thailand and can be very costly. There are not many applications in Thailand for divorce on the grounds of insanity however they do occur. You would also need to prove to the courts that your wife has been insane for a period of 3 continuous years and that she is incurable.
As you will note above that the path of insanity is based on two applications. One for divorce and the other to have the person declared insane. The courts cannot grant a divorce until it hears the claim of insanity as it affects the persons rights during a divorce if they are insane and do not have a competent guardian appointed.
To give an example is that John files for a divorce and applies to court for a divorce and an order to declare his Thai wife insane. If she is not found to be insane then the application will be dismissed and the application for divorce continued. If however she is found to be insane then the insanity application will be granted and the divorce application dismissed. Now if during the application process for insanity in terms of Section 1463 a guardian is appointed and the insanity declaration granted then the divorce will continue and the order granted based on the grounds of insanity.
Speak to a divorce lawyer in Thailand for more information about getting divorced as well as the complexities when dealing with a case of insanity.