diff --git a/doc/src/sgml/ref/drop_statistics.sgml b/doc/src/sgml/ref/drop_statistics.sgml
index 37fc4025891..8aacabac5ce 100644
--- a/doc/src/sgml/ref/drop_statistics.sgml
+++ b/doc/src/sgml/ref/drop_statistics.sgml
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-DROP STATISTICS [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable> [, ...]
+DROP STATISTICS [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ CASCADE | RESTRICT ]
 </synopsis>
  </refsynopsisdiv>
 
@@ -59,6 +59,18 @@ DROP STATISTICS [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable>
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term><literal>CASCADE</literal></term>
+    <term><literal>RESTRICT</literal></term>
+
+    <listitem>
+     <para>
+      These key words do not have any effect, since there are no dependencies
+      on statistics.
+     </para>
+    </listitem>
+   </varlistentry>
+
   </variablelist>
  </refsect1>