2. Willful and continued desertion for a period of twelve months,
3. Extreme cruelty,
4. Eighteen months of living separate and apart in different habitations,
5. Voluntarily induced addiction or habituation to any narcotic drug as defined by the Controlled Dangerous Substance Act or habitual drunkenness for twelve consecutive months subsequent to marriage and next preceding the filing of the complaint for divorce,
6. Institutionalization for mental illness for a period of 24 consecutive months subsequent to the marriage and next preceding the filing of the divorce complaint,
7. Imprisonment of the defendant for eighteen or more consecutive months subsequent to the marriage and preceding the filing of the complaint, provided that the parties have not resumed cohabitation following the defendant's release from imprisonment prior to the filing of the divorce complaint,
8. Deviant sexual conduct voluntarily performed by the defendant without the consent of the plaintiff,
9. Irreconcilable differences which have caused the breakdown of the marriage for a period of six months and make it appear that the marriage should be dissolved and that there is no reasonable prospect of reconciliation.