diff --git a/lib/migration.js b/lib/migration.js
index 1659f9fa..49813f67 100644
--- a/lib/migration.js
+++ b/lib/migration.js
@@ -823,8 +823,8 @@ function mixinMigration(PostgreSQL) {
           kind = i.kind;
         }
 
-        if (!kind && !type && typeof i === 'object' || i.unique && i.unique === true) {
-          kind = ' UNIQUE ';
+        if (!kind && !type && ((i && typeof i === 'object')? i.unique !== false : true)) {
+          kind = 'UNIQUE';
         }
 
         sql.push('CREATE ' + kind + ' INDEX ' + self.escapeName(iName) + ' ON ' + self.tableEscaped(model) +
@@ -852,8 +852,8 @@ function mixinMigration(PostgreSQL) {
           kind = i.kind;
         }
 
-        if (i.options && i.options.unique && i.options.unique === true) {
-          kind = ' UNIQUE ';
+        if (!kind && !type && ((i && typeof i === 'object')? i.unique !== false : true)) {
+          kind = 'UNIQUE';
         }
 
         sql.push('CREATE ' + kind + ' INDEX ' + iName + ' ON ' + self.tableEscaped(model) +