AGO178 was developed for the treatment of depression. A new formulation is being tested in the present study: a tablet to be placed and dissolved under the tongue (sublingual tablet). The goal of this trial was to study the pharmacokinetics of agomelatine given as sublingual tablet in participants with liver impairment and to compare the results to those of healthy volunteers who receive the same treatment.

Inclusion Criteria:

• Participants with liver disease confirmed within 3 months of screening.
• If liver impairment is caused by alcohol use, participants must have abstained from alcohol use within 3 months of study start.
• Participants must satisfy criteria for Child- Pugh Class A or B.

Exclusion Criteria:

• Use of other investigational drugs at the time of enrollment, or within 30 days or 5 half-lives of enrollment, whichever is longer.
• Pregnant or nursing (lactating) women.
• Women of child-bearing potential, defined as all women physiologically capable of becoming pregnant, unless using effective contraception during the study.
• Donation or loss of 400 millilitres (mL) or more of blood within eight (8) weeks prior to initial dosing.
• Significant illness within the two weeks prior to the dosing.
• Participants with Child-Pugh alterations due to a non-liver disease (e.g. cancer or treatment related weight loss).

Other protocol-defined inclusion/exclusion criteria may apply.