diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 328b0cd..6c0822b 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -20,7 +20,7 @@ jobs:
       run: python -m pip install tox
 
     - name: Run tox
-      run: tox
+      run: tox -v
 
   lint:
     runs-on: ubuntu-latest
diff --git a/README.md b/README.md
index 27bd8f4..3f5316e 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,7 @@ pip install pgspot
 ## Requirements
 
 - python >= 3.10
-- [pglast >= 3.13](https://github.com/lelit/pglast)
+- [pglast == 4.1](https://github.com/lelit/pglast)
 - [libpg_query](https://github.com/pganalyze/libpg_query) (through pglast)
 
 To install the runtime requirements, use `pip -r requirements.txt`.
diff --git a/requirements.txt b/requirements.txt
index 124b9f3..362d540 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1 @@
-pglast>=3.13
+pglast==4.1
diff --git a/setup.cfg b/setup.cfg
index d43b729..2daf4aa 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -28,7 +28,7 @@ packages = find:
 python_requires = >= 3.10
 
 install_requires =
-    pglast>=3.11
+    pglast==4.1
 
 tests_require =
     pytest
diff --git a/src/pgspot/visitors.py b/src/pgspot/visitors.py
index 29d6856..ce11979 100644
--- a/src/pgspot/visitors.py
+++ b/src/pgspot/visitors.py
@@ -77,6 +77,18 @@ def visit(self, node):
         if isinstance(node, dict):
             for key, value in node.items():
                 match (key):
+                    # work around inconsistent expression handling for assert and return statement in pglast
+                    case "PLpgSQL_stmt_assert":
+                        visit_sql(
+                            self.state,
+                            "SELECT " + value["cond"]["PLpgSQL_expr"]["query"],
+                        )
+                    case "PLpgSQL_stmt_return":
+                        if value:
+                            visit_sql(
+                                self.state,
+                                "SELECT " + value["expr"]["PLpgSQL_expr"]["query"],
+                            )
                     case "PLpgSQL_expr":
                         visit_sql(self.state, value["query"])
                     case _: