diff --git a/src/battle_ai_main.c b/src/battle_ai_main.c
index 8961f52b07..91e8046b7c 100644
--- a/src/battle_ai_main.c
+++ b/src/battle_ai_main.c
@@ -5661,7 +5661,8 @@ case EFFECT_GUARD_SPLIT:
                 break;
             case MOVE_EFFECT_SPD_MINUS_1:
             case MOVE_EFFECT_SPD_MINUS_2:
-                ADJUST_SCORE(IncreaseStatDownScore(battlerAtk, battlerDef, STAT_SPEED));
+                if (CanLowerStat(battlerAtk, battlerDef, aiData, STAT_SPEED))
+                    ADJUST_SCORE(IncreaseStatDownScore(battlerAtk, battlerDef, STAT_SPEED));
                 break;
             case MOVE_EFFECT_ATK_MINUS_1:
             case MOVE_EFFECT_DEF_MINUS_1:
@@ -5669,18 +5670,35 @@ case EFFECT_GUARD_SPLIT:
             case MOVE_EFFECT_SP_DEF_MINUS_1:
             case MOVE_EFFECT_ACC_MINUS_1:
             case MOVE_EFFECT_EVS_MINUS_1:
-                if (aiData->abilities[battlerDef] != ABILITY_CONTRARY)
-                    ADJUST_SCORE(DECENT_EFFECT);
+            {
+                u32 statId = STAT_ATK + additionalEffect->moveEffect - MOVE_EFFECT_ATK_MINUS_1;
+                if (CanLowerStat(battlerAtk, battlerDef, aiData, statId))
+                    ADJUST_SCORE(IncreaseStatDownScore(battlerAtk, battlerDef, statId));
                 break;
+            }
             case MOVE_EFFECT_ATK_MINUS_2:
             case MOVE_EFFECT_DEF_MINUS_2:
             case MOVE_EFFECT_SP_ATK_MINUS_2:
             case MOVE_EFFECT_SP_DEF_MINUS_2:
             case MOVE_EFFECT_ACC_MINUS_2:
             case MOVE_EFFECT_EVS_MINUS_2:
-                if (aiData->abilities[battlerDef] != ABILITY_CONTRARY)
-                    ADJUST_SCORE(DECENT_EFFECT);
+            {
+                u32 statId = STAT_ATK + additionalEffect->moveEffect - MOVE_EFFECT_ATK_MINUS_2;
+                if (CanLowerStat(battlerAtk, battlerDef, aiData, statId))
+                    ADJUST_SCORE(IncreaseStatDownScore(battlerAtk, battlerDef, statId));
                 break;
+            }
+            case MOVE_EFFECT_LOWER_ATTACK_SIDE:
+            case MOVE_EFFECT_LOWER_DEFENSE_SIDE:
+            case MOVE_EFFECT_LOWER_SPEED_SIDE:
+            case MOVE_EFFECT_LOWER_SP_ATK_SIDE:
+            case MOVE_EFFECT_LOWER_SP_DEF_SIDE:
+            {
+                u32 statId = STAT_ATK + additionalEffect->moveEffect - MOVE_EFFECT_LOWER_ATTACK_SIDE;
+                if (CanLowerStat(battlerAtk, battlerDef, aiData, statId))
+                    ADJUST_SCORE(IncreaseStatDownScore(battlerAtk, battlerDef, statId));
+                break;
+            }
             case MOVE_EFFECT_POISON:
                 IncreasePoisonScore(battlerAtk, battlerDef, move, &score);
                 break;
diff --git a/src/battle_ai_util.c b/src/battle_ai_util.c
index 84d247a617..c3d4b66965 100644
--- a/src/battle_ai_util.c
+++ b/src/battle_ai_util.c
@@ -2056,6 +2056,10 @@ bool32 CanLowerStat(u32 battlerAtk, u32 battlerDef, struct AiLogicData *aiData,
         case ABILITY_WHITE_SMOKE:
         case ABILITY_FULL_METAL_BODY:
             return FALSE;
+        case ABILITY_SHIELD_DUST:
+            if (!IsBattleMoveStatus(move) && GetActiveGimmick(battlerAtk) != GIMMICK_DYNAMAX)
+                return FALSE;
+            break;
         default:
             break;
         }
diff --git a/test/battle/ai/ai_check_viability.c b/test/battle/ai/ai_check_viability.c
index 4dff0e08ca..6d16d4fb6e 100644
--- a/test/battle/ai/ai_check_viability.c
+++ b/test/battle/ai/ai_check_viability.c
@@ -391,3 +391,21 @@ AI_SINGLE_BATTLE_TEST("AI uses Wide Guard against Earthquake when opponent would
         TURN { MOVE(player, MOVE_EARTHQUAKE); EXPECT_MOVE(opponent, MOVE_WIDE_GUARD); }
     }
 }
+
+AI_SINGLE_BATTLE_TEST("AI sees Shield Dust immunity to additional effects")
+{
+    u32 ability;
+    PARAMETRIZE { ability = ABILITY_SHIELD_DUST; }
+    PARAMETRIZE { ability = ABILITY_TINTED_LENS; }
+
+    GIVEN {
+        AI_FLAGS(AI_FLAG_CHECK_BAD_MOVE | AI_FLAG_CHECK_VIABILITY | AI_FLAG_TRY_TO_FAINT | AI_FLAG_OMNISCIENT);
+        PLAYER(SPECIES_VENOMOTH) { Ability(ability); Moves(MOVE_CELEBRATE, MOVE_POUND); }
+        OPPONENT(SPECIES_WOBBUFFET) { Moves(MOVE_CHILLING_WATER, MOVE_BRINE); }
+    } WHEN {
+    if (ability == ABILITY_SHIELD_DUST)
+        TURN { EXPECT_MOVE(opponent, MOVE_BRINE); }
+    else
+        TURN { EXPECT_MOVE(opponent, MOVE_CHILLING_WATER); }
+    }
+}