point is under the law, a person of unsound mind, does not have a legal capacity at all..and even more specifically in marriage acts..the thing is that activists are pressing for legal status for them..but its not yet happened - I think thats what artee is talking about - the disabilities bill which is yet to be enacted..because of the debate around whether a person with unsound mind can be a party to contracts at all..
  
 health related is different - our law doesnt even allow euthanasia..basically everybody has a right to live..but not choose death, hence a guardian is allowed to take calls for the patient with unsound mind..
  
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 Under Hindu Marriage Act, 1955, conditions in respect of mental disorders, which must be fulfilled before the marriage is solemnized under the Act, are as follows.
  - Neither party is incapable of giving a valid consent as a consequence of unsoundness of mind.
  - Even if capable of giving consent, must not suffer from mental disorders of such a kind or to such an extent as to be unfit for marriage and the procreation of children.
  - Must not suffer from recurrent attacks of insanity.
 
 The expression "mental disorder" means mental illness, arrested or incomplete development of mind, psychopathic disorder or any other disorder or disability of mind and includes schizophrenia. The expression "psychopathic disorder" means a persistent disorder or disability of the mind (whether or not including sub-normality of intelligence) which results in abnormally aggressive or seriously irresponsible conduct on the part of the other party, and whether or not it requires or is susceptible to medical treatment.
Marriages in contravention to the provision in respect of mental disorders come under voidable category. Voidable marriages (sec 12) are those which may be annulled by a decree of nullity on the given grounds but may continue to be legal till the time it is annulled by a competent court.
According to the section 13 of the Act, divorce or judicial separation can be obtained if the person has been incurably of unsound mind, or has been suffering continuously or intermittently from mental disorder of such a kind and to such an extent that the petitioner cannot reasonably be expected to live with the respondent.
The expression "incurably" of unsound mind cannot be so widely interpreted as to cover feeble minded persons or persons of dull intellect who understand the nature and consequences of the act and are therefore able to control them and their affairs, and their reaction in the normal way (A.I.R. 1969 Guj-48 and 78 CLT 1994 561). When there was sufficient evidence for the court to conclude that the slight mental disorder of the wife was not of such a kind and to such an extent that the husband could not reasonably be expected to live with her, divorce could not be granted (A.I.R., 1982 CAL 138). Each case of schizophrenia has to be considered on its own merits. [16]
Under Special Marriage Act, 1954, the grounds for marriage, divorce and judicial separation are practically the same as those in the Hindu Marriage Act, 1955. The Special Marriage Act, 1954 is meant for any person in India and Indian nationals abroad, irrespective of the faith that the individual may profess. A marriage solemnized in any other form can be registered under this Act.
Under the prevalent Muslim Law, marriage is a type of contract. Therefore, a Muslim who is of sound mind and has attained puberty is qualified to marry. However, if the guardian of a person of unsound mind considers such a marriage to be in his interest and in the interest of society and is willing to take up all the monetary obligations of the marriage, then such a marriage can be performed. Talaq (divorce) under Muslim Law has to be for a reasonable cause and must be preceded by attempts for reconciliation by two arbiters. According to Muslim Marriage Act, 1939, a woman married under Muslim Law is entitled to obtain a decree of divorce if her husband has been insane for a period of 2 years.
Under Christian Law, marriage is voidable, if either party was a lunatic or idiot. Christians can obtain divorce under Indian Divorce Act. 1869 (as amended in 2001) on grounds of unsoundness of mind provided: (i) it must be incurable (ii) it must be present for at least 2 years immediately preceding the petition. Divorce is not admissible on ground of mental illness under the Parsi Marriage and Divorce Act, 1936. However, divorce can be obtained if the defendant at the time of marriage was of unsound mind, provided the plaintiff was ignorant of the fact and the defendant has been of unsound mind for a period of 2 years upwards and immediately preceding the application.