Psionics in Dungeons & Dragons Part III: Comparing OD&D and AD&D

Before reading through this post, it's a good idea to look back over my posts on How Psionics Work in OD&D, and How Psionics Work in AD&D. These will give a solid overview of the systems in place, and establish how straightforward and easy to use psionics actually are in these games, despite their long-running reputation for being overcomplicated or arcane.

The Core Concepts

The use of psionics in D&D is a fairly simple affair: first, you roll to see if you have the capability. Then, you roll to see how strong that capability is. Finally, you determine which psionic attack and defense modes you know, and which powers you learn.

Abilities (attack and defense modes and powers) are used by spending psionic strength points.

Psionic combat is resolved by comparing attack mode and psionic strength of the attacker vs. defense mode on a matrix, or based on a saving throw if the victim is a non-psionic.

These basic concepts are the same across both versions of the rules.

Now, let's look at where they diverge, and they diverge in some very important ways. In general, psionics in OD&D are far more powerful than they are in AD&D.

Who Can Be Psionic?

In OD&D, only humans can be psionic, and then only if you're neither a druid nor a monk. This means that only human fighting men, paladins, rangers (see The Strategic Review), clerics, magic users, illusionists (see The Strategic Review), thieves, assassins, and bards (see The Strategic Review) can be psionics, with rangers, illusionists, and bards counted as additional sub-classes of fighter, magic user, and thief, respectively. 

Note that the Strategic Review classes are not expressly mentioned in Eldritch Wizardry; that book merely states that druids and monks are the only classes without psionic potential. The DM could just as easy determine that applies to Strategic Review classes as well. 

In AD&D, on the other hand, any human class (including druids and monks) can be psionic, and at the DM's discretion, the ability may extend also to halflings and dwarves. So the options for psionic characters are increased in AD&D. 

Psionic Potential

It's much harder to actually be psionic in AD&D. In OD&D, a character has a flat 10% chance (91-00 on d%) to be psionic. In AD&D, a character has a 1% chance of being psionic, with the chance improving based on having high ability scores.

Learning Powers

The first and most important difference between the two systems is that psionics in OD&D will likely have many more powers than they will in AD&D. 

In OD&D, there is an increasing chance each level that a character will learn a new power, and the chance to learn two powers at once on any given level. Your chance also increases or decreases based on your intelligence, wisdom, and charisma scores. This can result in characters with ten or more powers, and a solid mix of both superior and basic, as they level up. 

Attack modes and defense modes in OD&D are racked up as the character acquires abilities--one attack or defense mode per every 3-5 powers (defending on mode and character class) the character gains. Eventually, it's likely that an OD&D character will have all ten attack and defense modes, as well as a dozen or more powers. 

In addition, when a character's chance to learn powers reaches 100%, they can simply choose what powers they want. In OD&D, superior powers can be gained so long as the character doesn't have more advanced than basic powers. 

In AD&D, characters roll once for the total number of powers they will ever learn, for attack modes, defense modes, and disciplines (powers), at first level, with your roll adjusted by high scores in intelligence, wisdom, or charisma, but not adjusted downward for lower scores. They get all their attack and defense modes right away, choosing which ones they like. They then roll randomly to see what disciplines they develop every other level (levels 1, 3, 5, 7, etc.)

In AD&D, no character will ever have more than two Major powers, and must obtain all Minor powers they roll before they can get a single Major power. So if your roll indicates 4 minor powers and 2 major powers, you'll be 9th level before you get your major power, whereas in an OD&D game, you could have a superior power by second level. 

Power Points

Characters in OD&D are also likely, based on the ways the formulae work, to have far higher numbers of strength points, and their points will go much further in terms of powering abilities. 

In OD&D, for example, your total psionic strength is double your psionic attack (or your psionic attack plus your psionic defense--they are the same, in the beginning). When you spend points for attack modes, they come off of both psionic attack strength and total psionic strength. Likewise for psionic defense. When you spend points for powers, every two points you spend reduces attack and defense by one each. 

In AD&D, the numbers are the same. However, in order to fuel powers, you must spend one point from each of psionic attack strength and defense strength--effectively halving the number of points you can spend to power abilities. 

Power Balance

In OD&D, due to the sheer potential power of psionics, there are balances built into the system, which de-power the base class with each psionic power learned. Fighters lose strength and followers, thieves lose dexterity, magic users lose spell levels, and clerics lose both spell levels and effective levels in turn undead. 

The balancing issues are fare different in AD&D--instead of robbing classes of their default powers, they receive far fewer points to power psionic abilities, which are in turn more expensive to use (some abilities with zero cost in OD&D have a cost of 1 point / round in AD&D). 

Distribution of Abilities

In OD&D, power availability is based on class--there are a total of twenty abilities available to fighters and thieves, while clerics and magic users have a list of 18 powers each. There is some crossover, and some abilities are exclusive to each class. 

In AD&D, this is not the case. While some abilities have differing effects for different classes (and these are very few in number), pretty much any class can obtain any psionic discipline.

Psionic Combat

The function of psionic combat in each system is largely the same, barring a few minor details (attacking a non-psionic in OD&D requires a total Psionic Strength of over 120, while in AD&D it requires an attack strength of at least 100). The full list of effects of specific powers are altered somewhat on the matrices--the specific differences are numerous enough that it would be onerous to list them here--it's left to individual readers to spot them on the tables. What is important is that the actual procedures remain the same. 

AD&D is more clear and codified. In OD&D, for example, it is left to interpretation how the choice of defense mode is made when attacked; in AD&D it is clear that the best available defense mode always activates, assuming there are points to activate it. 

In OD&D, damage suffered from psionic combat comes off of total psionic strength, affecting both attack and defense equally on a 2:1 ratio. In AD&D, damage suffered from psionic attack comes off of psionic defense, and only comes off of psionic attack strength when defense runs out and "attacks on a defenseless psionic" are used. 

The combat matrices are cleaner and easier to read in AD&D, because the layout is more advanced, and the specific bonuses and modifiers for non-psionic saving throws are more expansive and clear. In addition, the effects a psionic blast has upon a non-psionic, or the effects of a psionic attack against a defenseless psionic, are more varied and can be more brutal in AD&D.

One major difference in terms of psionic combat is that in AD&D, there is no initiative, and no surprise. This makes a huge difference, as surprise in OD&D puts a psionic character at a MAJOR disadvantage, allowing the attack to take place on the "Defenseless Psychic" table (called the Special Attack Matrix in OD&D). In AD&D, if you have the points and the defense mode, you can always defend. 


In the end, the two systems are similar, but have some very core differences--enough to not be directly compatible or interchangeable. Either will function in either edition of the game on its own, but they can't be seamlessly mixed and matched. It is my opinion that the AD&D version represents (as it should) a more refined, clarified, and balanced system overall. Neither system, however, is complicated, arcane, or un-usable, nor are they unbalancing to a game. 

It's little secret that Gary Gygax himself did not like psionics; that he wasn't the sole author of the system, and didn't include it in his games. It was designed originally simply to expound upon waht the Mind Flayer could do, and got out of hand. It was Tim Kask who designed the psionic combat system. The following two quotes are telling:

Gary Gygax: As for the psionics, that can of worms was my doing. I had created the mind flayer as a fine monster, and I should have left well enough alone; but no! I had to add mental powers, send the initial draft around. I soon hated the whole business, but Len Lakofka and his group in Chicago loved the concept, and Tim was enthused about the addition as well. So, as said Pilate, I washed my hands of the matter.

Tim Kask: I LOVED psionic combat and had great fun devising it with all of its tables and charts. Apparently I was in the tiny minority. I guess mental combat was too esoteric for most D&Ders; not enough of them shared my fondness for the Dr. Strange Marvel comics and Mindflayers. God, I loved Mindflayers; they were all over my dungeons. I just loved the idea of turning an annoying PC into a gibbering idiot.. Oh well, live and learn...

There's a lot of people that agree with Gary, that psionics simply don't have the right feeling for D&D, and that's perfectly fine. I can't argue with that, nor should anyone. To me, however, D&D is a lot of different things, and depending on the setting you're exploring, they can add a lot of excitement, mystique, and fun to the game.

Certainly one of the biggest hurdles is that you can't go in partway. If you don't adopt psionics wholesale, you may as well not use them at all: the one psionic in your game will either be a powerhouse, or rarely get to use their powers, or both.

A DM wishing to incorporate psionics into their game has to go in all the way, and that means NPCs and monsters with psionic powers as well. This alone can be a hurdle, especially in an ongoing game. Even in a new campaign it can represent additional bookkeeping and planning, so a DM should be prepared for that element.

I hope this blog series has managed to shine some light on the arcane, mysterious, and ultimately fairly straightforward psionics system in the original and advanced versions of the D&D rules set.

More on D&D and Psionics

There have been volumes of blogs and articles online written about D&D psionics, their background, and how Gygax felt about them. Here's just a few good ones:


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