Understanding Psionics in Advanced Dungeons & Dragons
- Dungeoneers Guild Games
- Sep 21
- 19 min read
Updated: Oct 31
This article unravels those confusing psionic rules of First Edition AD&D and reveals how they work.
By R. Nelson Bailey
Introduction
Psionics in First Edition Advanced Dungeons & Dragons (AD&D) are an optional subsystem of mental powers drawn from the minds of creatures. Their inclusion adds a rare and unconventional dimension to a campaign. Characters with psionics enjoy a clear advantage over non-psionic adventurers: they are never without tools, whether spellbook, prayer, or sword. These powers can replicate spell effects without memorization, components, or divine favor, giving psionic characters flexibility unmatched by others. Yet psionics are not without cost. Their use invites psionic monsters, requires complex mental combat, risks the loss of powers, and demands more bookkeeping from both player and Dungeon Master (DM).
Psionic abilities have long been a staple of science fiction and science fantasy, often portrayed as “mental magic” wielded by mesmerists, seers, mutants, and alien beings. Classic examples include telepathy, telekinesis, and empathy. The American science fiction writer — and Appendix N alumnus — Jack Williamson (1908–2006) is credited with coining the term psionics in 1951. Since then, psychic powers have featured prominently in the works of Roger Zelazny, Leigh Brackett, Sterling Lanier, and many others.
Dungeons & Dragons first introduced psionics in Eldritch Wizardry (1976). With the release of the First Edition Advanced Dungeons & Dragons in 1977, the system was revised. Later, Dragon Magazine Issue 78 (October 1983) presented the unofficial psionicist character class, elevating psionics from a marginal option to a more central feature. Psionics expanded further in Second Edition AD&D, and with the publication of The Complete Psionics Handbook (1991), many design issues were addressed, and the psionicist became an official character class.
The inclusion of psionics in Dungeons & Dragons has often seemed like an afterthought, never fully integrated into the game’s core design. Some players view these powers with suspicion, arguing that mental abilities have no place in a fantasy setting. Yet the assumption that science fiction and fantasy must remain separate is unfounded. Elements of science fiction have been present in D&D since the beginning — the Original D&D set even suggested robots, androids, and cyborgs as potential encounters.[1] Many of the authors in Appendix N wrote science fiction outright or freely blended it with fantasy. Even the great myth-maker Tolkien was not a strict fantasy purist; his goblins found delight in “engines and explosions.”[2]
Many Dungeon Masters and players dismiss the First Edition AD&D psionic system as broken. They argue it is overpowered, confusing, clumsy, or unnecessary — leading many groups to ignore the rules altogether.
These criticisms have merit, but much depends on one’s perspective and expectations. The rules are murky and poorly organized, yet not irreparably flawed. The rules are indeed murky and poorly organized, yet they are not irreparably flawed. With careful reading and clear interpretation, the psionic system can be understood and integrated into a campaign.
[1] Gary Gygax & Dave Arneson. Volume III: The Underworld & Wilderness Adventures (Tactical Studies Rules, 1974), p. 11.
[2] Tolkien, J.R.R., The Hobbit (Houghton, 1966), p. 73.
How Psionics Work
This section offers a step-by-step explanation of how psionics are gained, calculated, and used in First Edition Advanced Dungeons & Dragons. It covers the procedures from the Players Handbook (pp. 110–111) for determining psionic potential, computing psionic strength, and assigning disciplines and modes. It also outlines the psionic combat rules from the Dungeon Masters Guide (pp. 76–79) and addresses some of the more perplexing questions surrounding their use.
Determining Psionic Potential
Characters check for psionic potential when they are first created or whenever their Intelligence, Wisdom, or Charisma score increases to 16 or higher.[3]
1. Requirements
Allowed Races: Only humans, dwarves (all), halflings (all), grugach elves,[4] and valley elves[5] can possess psionic abilities. The possibility exists that drow[6] and other elves (gray, high, and wood) [7] [8] may also possess psionic abilities.
Ability Scores: The character must have a score of 16 or higher in at least one of the following: Intelligence, Wisdom, or Charisma.
2. Base Chance
The base chance of psionic potential is 1%.
3. Ability Score Modifiers
Apply the following modifiers if the score is 17 or 18:
Intelligence (17–18): +2.5% per point.
Wisdom (17–18): +1.5% per point.
Charisma (17–18): +0.5% per point.
Example: A player checks whether a magic-user character possesses psionic abilities, given Intelligence 18, Wisdom 16, and Charisma 18. The character’s ability score modifiers are as follows:
Intelligence: 2.5% × 2 = 5%
Wisdom: 0%
Charisma: 0.5% × 2 = 1%
The total bonus is 6%, added to the base 1% for a 7% chance that the character has psionic abilities. The character succeeds if they roll 01–07 on percentile dice.
[3] “Sage Advice” (Dragon, Issue 78, Oct. 1983), p. 16.
[4] Gary Gygax, Advanced Dungeons & Dragons Monster Manual II (TSR, 1983), p. 63.
[5] Gygax, Monster Manual II (TSR, 1983), p. 63.
[6] Don Turnbull (editor), Advanced Dungeons & Dragons Fiend Folio (TSR, 1981), p. 33.
[7] “Sage Advice” (Dragon, Issue 78, Oct. 1983), p. 16. Later rules seem to suggest — namely through the inclusion of grugach and valley elves as possessing psionics — that this inclusion may apply to all elf sub-races.
[8] “Sage Advice” (Dragon, Issue 42, Oct. 1980), p. 23.
Determining Psionic Ability Points
The player now tabulates the character’s Psionic Ability score. The score indicates the number of points the character can use to employ Attack and Defense Modes, as well as disciplines. It also determines the character’s Total Psionic Ability (or Strength) score.
1. Base Psionic Score
Roll d100 to determine the character’s Base Psionic Score.
2. Modified Psionic Score
Add 1 point for each point of Intelligence, Wisdom, and Charisma between 13–18.
If two of these ability scores are 17 or greater, double the subtotal.
If all three are 17 or greater, quadruple the subtotal.
3. Psionic Ability Score
Psionic Ability = Base Psionic Score + Modified Psionic Score.
4. Total Psionic Ability and Strength
A character’s Total Psionic Ability equals their Psionic Ability score multiplied by two. This value, which ranges from 10 to 344 points, is fixed and does not vary. Total Psionic Strength is equivalent to Total Psionic Ability, but the term is used specifically in the context of psionic combat. During psionic combat, its value fluctuates and is recalculated at the start of each segment to reflect Attack and Defense Mode expenditures for that round.
The Total Psionic Strength is divided into two pools of points, Attack Strength and Defense Strength.
Attack Strength = ½ Total Psionic Ability.
Defense Strength = ½ Total Psionic Ability.
Example —
The player rolls 54 for the magic-user’s Base Psionic Score.
18 Intelligence = +6
16 Wisdom = +4
18 Charisma = +6
Subtotal = 16. This doubled (two scores are 17+) = 32
Psionic Ability = 54 + 32 = 86
Total Psionic Ability or Strength = 86 × 2 = 172. Of this, 86 points are for Attack Strength and 86 for Defense Strength.
Determining Psionic Powers
The player determines the character’s number of Attack Modes, Defense Modes, and Psionic Disciplines.
Attack and Defense Modes are used in psionic combat (see below).
Disciplines represent a wide range of abilities, many of which resemble or replicate spell-like effects (see below).
Attack and Defense Modes
In addition to disciplines, psionic characters determine their Attack Modes and Defense Modes by random roll. Except for Psionic Blast, Attack Modes are used to strike psionic opponents in mental combat. Defense Modes protect their user against psionic attacks.
The character receives all of their rolled Attack and Defense Modes immediately upon gaining psionic abilities.
For descriptions of psionic Attack and Defense Modes, refer to the Players Handbook, p. 110.
Number and Type of Attack Modes
The player rolls on the table below to determine how many Attack Modes a character possesses.
Number of Attack Modes Table (from Players Handbook, p. 110)
Once the number of Attack Modes is known, the player then selects the modes from the table below.
Psionic Attack Modes (from Players Handbook, p. 110)
Attack Mode Notes —
Point Cost per Usage: This shows the number of psionic Attack Points that the attacker must expend in using the attack mode.
Medium Range: Attacks reduce damage by 20%, fractions rounded up.
Long Range: Attacks reduce the attacker’s effective Total Psionic Strength by one category (25 points) and reduce damage by 20%, fractions rounded up. If already in the 01–25 strength range, damage is reduced 50%, and fractions are dropped.
Note: If all attack points are expended, or too few remain to use any Attack Mode listed, the creature may defend only.
Psionic Blast: This Attack Mode may be directed against non-psionics only if the attacker’s current Attack Strength is 100 or greater; with 99 points or fewer, the attempt cannot be made. Non-psionic characters struck by a psionic blast are permitted a saving throw vs. Spells to resist its effects. Range, race, mental state, and the influence of certain magics may all modify this saving throw. For full details, see the Dungeon Masters Guide, p. 78.
Psychic Crush: The user of this Attack Mode may defend solely with Defense Mode G: Thought Shield, or with no defense at all.[9] Psychic Crush carries a percentage chance of killing the opponent outright; it does not diminish Defense Strength, and if the roll fails, it has no effect. Refer to Table IV.A: Psionic vs. Psionic in Mental Combat (see Dungeon Masters Guide, p. 76) for the percentage chance of death.
See Players Handbook, p. 110, for a full description of each Attack Mode.
[9] “Sage Advice” (Dragon, Issue 78, Oct. 1983), p. 18.
Number and Type of Defense Modes
The player rolls on the table below to determine how many Defense Modes a character possesses.
Number of Defense Modes Table (from Players Handbook, p. 110)
Once the number of Defense Modes is known, the player selects each one on the table below.
Psionic Defense Modes (from Players Handbook, p. 110)
Defense Mode Notes —
Required Defense Mode: Every psionic individual automatically has Defense Mode F: Mind Blank.[10]
Selection of Modes: The player selects all other Defense Modes.[11] If a monster or non-player character, the DM chooses or determines randomly.
Point Cost per Usage: The number of psionic defense points expended by the defender to activate a given mode when under attack.
Area Protected: If a defense mode extends beyond the individual, it grants either its own protection or that of the defense mode employed by any individual within its radius—whichever is greater.
Thought Shield: A psionic user can employ this Defense Mode even while taking another action, such as engaging in melee or casting a spell.[12] Furthermore, this is the only Defense Mode that a user of Psychic Crush can use.[13]
See Players Handbook, p. 110, for a full description of each Defense Mode.
[10] Gary Gygax, Advanced Dungeons & Dragons Players Handbook (TSR, 1978), p. 110.
[11] Gygax, Players Handbook, p. 110.
[12] “Sage Advice” (Dragon, Issue 78, Oct. 1983), p. 18.
[13] “Sage Advice” (Dragon, Issue 78, Oct. 1983), p. 18.
An Example of Acquiring and Selecting Attack and Defense Modes
The player rolls a d100 to determine the number of Attack and Defense Modes that the magic-user character possesses.[14]
Attack Modes: A roll of 71 corresponds to three Attack Modes. The player selects Mind Thrust, Id Insinuation, and Psychic Crush.
Defense Modes: A roll of 28 corresponds to three Defense Modes. Mind Blank is automatically granted; therefore, the player selects Thought Shield and Tower of Iron Will as the remaining two abilities.
[14] Gygax, Players Handbook, p. 111.
Psionic Disciplines
The character rolls on the Psionic Discipline Table to determine available powers. Disciplines are divided into minor and major categories.
Number of Disciplines (from Players Handbook, p. 111)
Determining Psionic Disciplines
Players roll on the table to determine their psionic character’s minor disciplines (devotions) and major disciplines (sciences). For monsters, the Dungeon Master rolls randomly or selects them as desired.
Table of Psionic Disciplines (from Players Handbook, p. 111)
* Consult your DM for their ruling on this result.
Example —
A psionic character rolls a d100 and obtains 70. Referring to the Psionic Disciplines Table, this grants three minor disciplines and one major discipline. The player then rolls on the Table of Psionic Disciplines to determine each discipline.
Minor disciplines: Rolls of 1, 43, and 77 yield Animal Telepathy, ESP, and Reduction.
Major discipline: A roll of 57 yields Probability Travel.
Acquiring Disciplines
Upon gaining psionic abilities, the character begins with at least one minor discipline.
For every two levels gained thereafter, the character acquires one additional discipline, until the limit established by random roll is reached.[15]
Minor disciplines are gained first. Major disciplines may only be selected once all minor disciplines available to the character have been obtained.[16]
When multiple disciplines are granted, the order of acquisition is determined randomly. The character gains disciplines as they advance in level, according to the following sequence:
Level 1: ESP (minor)
Level 3: Reduction (minor)
Level 5: Animal Telepathy (minor)
Level 7: Probability Travel (major)
See Players Handbook, pp. 111–116, for descriptions of each psionic discipline.
[15] Gygax, Players Handbook, p. 111.
[16] Gygax, Players Handbook, p. 111.
Levels of Mastery
All psionic disciplines possess a Mastery Level, which determines the efficacy of their power. This functions analogously to a spellcaster’s caster level. The Mastery Level of each discipline is equal to the user’s current level of experience.
Using a Psionic Power
Each psionic power requires expenditure of psionic points when used:
Attack Modes consume points from the Attack Strength pool.
Defense Modes consume points from the Defense Strength pool.
Disciplines consume 1 Attack Strength point and 1 Defense Strength point per Point Cost.[17]
[17] Gygax, Players Handbook, p. 111.
Example —
A character employs the Empathy discipline, which costs 3 strength points per use. With 86 Attack Strength and 86 Defense Strength, the character subtracts 3 points from each pool every time the power is activated.
Psionic Combat
Psionic combat is a form of mental dueling that occurs only between two psionic beings. Psionic combat rounds are divided into 10 segments per round. During this time, the combatants can use an Attack Mode or a discipline in addition to a Defense Mode.[18] They may take no action (e.g., make a physical attack or cast a spell) during psionic combat. Combat surprise rules do not apply to psionic combat,[19] as a defender automatically initiates a Defense Mode when psionically attacked.[20]
A combatant cannot launch a psionic attack if struck with a physical or spell-based attack from an opponent. However, they may still employ a Defense Mode.[21]
Zero Defense Strength: In mental combat, when a psionic opponent’s Defense Strength points are reduced to zero, the attacker consults Table IV.B: Psionic Attack upon Defenseless Psionic (see Dungeon Masters Guide, p. 77). Further psionic attacks against a defenseless opponent may cause death or other debilitating effects, as noted on the table.
Zero Attack Strength: When a psionic combatant’s Attack Strength reserve is reduced to zero, any further psionic damage is applied directly as physical damage, reducing the defender’s hit points on a one-for-one basis.[22]
[18] Gary Gygax, Advanced Dungeons & Dragons Dungeon Masters Guide (TSR, 1979), p. 79.
[19] “Sage Advice” (Dragon, Issue 78, Oct. 1983), p. 16.
[20] Gygax, Dungeon Masters Guide, p. 79.
[21] Gygax, Players Handbook, p. 117.
[22] Gygax, Dungeon Masters Guide, p. 77.
Sequence of Psionic Combat
At the start of each combat segment, both combatants proceed as follows:
Determine Psionic Strength: Each combatant calculates their current Total Psionic Strength, which is their current Attack Strength and Defense Strength added together.
Select Attack Mode: Each combatant secretly chooses the Attack Mode to be employed for that segment.
Select Defense Mode: Each combatant secretly chooses the Defense Mode to be employed for that segment.
Resolve Mental Combat: Compare chosen Attack and Defense Modes using Table IV.A: Psionic vs. Psionic Combat (Dungeon Masters Guide, p. 76).
The attacker’s chosen mode is compared against the defender’s Defense Mode.
Simultaneously, the opponent’s chosen mode is compared against the other’s Defense Mode.
All attacks are resolved simultaneously.
Any Defense Points lost are subtracted from the defender’s pool.
Repeat: Continue until one combatant has expended all Defense Points. When this occurs, the victor consults Table IV.B: Psionic Attack Upon Defenseless Psionic to resolve the outcome.
Example of Psionic Combat
While exploring a dungeon, the psionic magic-user player character encounters a mind flayer. Upon spotting one another, they engage in psionic combat.
Segment 1
Magic-User: Current Total Psionic Strength is 172. The player selects Thought Shield (defense) and Psychic Crush (attack).
Mind Flayer: The DM sets Psionic Strength at 262. Its only attack mode is Psionic Blast. For Defense Modes, this creature has Mind Blank, Thought Shield, and Mental Barrier. The DM selects Mental Barrier.
Note: The Monster Manual incorrectly lists mind flayers as having Attack Mode B: Mind Thrust; their correct mode is A: Psionic Blast.[23]
[23] “Dispel Confusion” (Polyhedron, Issue 26, 1985), p. 23.
Resolution:
Psychic Crush vs. Mental Barrier: This attack has a 14% chance to kill the mind flayer. The player rolls 21 — no effect.
Psionic Blast vs. Thought Shield: Costs the magic-user 27 Defense Points.
End-of-Segment Totals:
Magic-User: At the start of the segment, the character has 172 Total Psionic Strength. Attack and Defense Strength are divided evenly at 86 each. The Psychic Crush costs 14 points, reducing his Attack Strength to 72 (86 – 14 = 72). Thought Shield costs 2 points, and resisting Psionic Blast costs another 27, a total of 29. This reduces his Defense Strength to 57 (86 – 29 = 57). At the end of the segment, his new Total Psionic Strength is 129 (72 + 57).
Mind Flayer: The creature begins the segment with 262 Total Psionic Strength, divided into 131 Attack and 131 Defense. The Psionic Blast costs 20 points, reducing its Attack Strength to 111 (131 – 20 = 111). The Mental Barrier costs 3 points, lowering its Defense Strength to 128 (131 – 3 = 128). At the end of the segment, its new Total Psionic Strength is 239 (111 + 128).
Segment 2
Magic-User: Total Psionic Strength is 129. Anticipating Psionic Blast, the player switches to Tower of Iron Will (defense) and Mind Thrust (attack).
Mind Flayer: Total Psionic Strength is 239. Uses Psionic Blast (attack) and selects Thought Shield (defense).
Resolution:
Mind Thrust vs. Thought Shield: Costs the mind flayer 24 Defense Points.
Psionic Blast vs. Tower of Iron Will: Costs the magic-user 7 Defense Points.
End-of-Segment Totals:
Magic-User: Attack Strength drops from 72 to 68 after paying the 4-point cost of Mind Thrust. Defense Strength falls from 57 to 40 — 10 points for Tower of Iron Will and 7 more from resisting another Psionic Blast. His new Total Psionic Strength is 108 (68 + 40).
Mind Flayer: Attack Strength drops from 111 to 91 after expending 20 points on Psionic Blast. Defense Strength is reduced by 26, from 128 to 102, due to maintaining Thought Shield and resisting Mind Thrust. Its new Total Psionic Strength is 193 (91 + 102).
After two rounds, the magic-user has fallen from 172 to 108 points, while the mind flayer has declined only slightly, from 262 to 193. The duel is turning against the adventurer, who risks slipping into the Defenseless Psionic state if the combat continues.
General Rules on the Use of Psionics
Actions While Using Psionics: A psionic creature cannot make physical attacks, cast spells, or employ disciplines while using an attack mode. It may, however, maintain a Defense Mode while performing these actions.[24]
Psionic Use While Held: Because psionics originate solely from the mind, characters can employ psionic powers even when immobilized — for example, when grappled, bound, or under the effect of a hold person spell.[25]
Initialization Time: All disciplines require one segment to employ.[26] Attacks made against the user do not disrupt or spoil their initialization.
Psionic Linking: Two or more psionic creatures may link their minds to extend the range of a discipline or to increase combat strength and effectiveness. See Players Handbook, p. 117, for complete details.
Recovering Psionic Points: Expended psionic points regenerate at an hourly rate determined by the character’s level of physical exertion. See Players Handbook, p. 117, for complete details.
[24] “Dispel Confusion” (Polyhedron, Issue 3, Winter 1981), p. 5.
[25] “Sage Advice” (Dragon, Issue 76, Aug. 1983), p. 64.
[26] “Dispel Confusion” (Polyhedron, Issue 30, 1985), p. 29.
General Rules on Psionic Potential & Ability Scores
Psionic Potential Checks: Characters check for psionic potential when they are first created or whenever their Intelligence, Wisdom, or Charisma score increases to 16 or higher.[27]
Ability Score Reduction: If Intelligence, Wisdom, or Charisma drops below 16, the character loses their psionic abilities.[28] A permanent reduction in a score results in the permanent loss of powers. If a score is lowered at any time, the player must recalculate the character’s Psionic Ability score.
Level Loss: If a psionic character loses an experience level, such as from an undead’s energy drain ability, it reduces the character’s Mastery Level and any disciplines they might have gained.[29]
[27] “Sage Advice” (Dragon, Issue 78, Oct. 1983), p. 16.
[28] “Sage Advice” (Dragon, Issue 78, Oct. 1983), p. 16.
[29] “Dispel Confusion” (Polyhedron, Issue 3, Winter 1981), p. 5.
Monsters’ Psionic Capabilities
Many monsters in AD&D possess psionic powers. Each psionic creature’s entry in the Monster Manual, Monster Manual II, and Fiend Folio lists its Total Psionic Ability along with its known Attack and Defense Modes. However, not all entries specify the number or types of disciplines a monster knows. For example:
The couatl and shedu entries note the number of minor and major disciplines but do not identify the specific ones.
The entries for psionic demons list neither the number, type, nor names of disciplines.
The duergar entry, by contrast, specifies the exact disciplines known.
The table below provides the number and types of Attack and Defense Modes a psionic creature possesses when such information is not provided in its description.[30] It also indicates the number and types of disciplines to be assigned by the DM based on the creature’s Psionic Strength score. When disciplines are not specified, determine them randomly using the Table of Psionic Disciplines (see above or on p. 111 of the Players Handbook). Do not use this table if the monster’s entry already provides this information.
* Beings listed as Class VI cannot use psionics and are invulnerable to any type of psionic attack, including Psionic Blast.
[30] Gygax, Monster Manual II, p. 7.
Psionic Encounters
If a campaign employs psionics, some random encounters may involve psionically endowed creatures. The use of psionic powers — or spells resembling them — draws the attention of such creatures within the area of effect.[31] Whenever a creature expends psionic points using an Attack Mode, Defense Mode, or a discipline, other psionic-using creatures can detect that creature at a range of 30’ per level or Hit Die.[32] However, any creature employing mind bar or psionic invisibility cannot be detected. When used within one turn of a random encounter check, there is a 25% chance that the encounter will involve psionic beings. Roll on the table below to determine the type and number of psionic monsters encountered.
Psionic Encounter Table
[31] Gygax, Dungeon Masters Guide, p. 182.
[32] “Sage Advice” (Dragon, Issue 78, Oct. 1983), p. 18.
Psionically-Capable Monsters in AD&D
* Some individuals may possess psionic abilities. Determine this using the standard rules for psionic potential.
** Fiend Folio notes that drow psionic abilities are “unknown,” which leaves open the possibility of some individuals possessing psionic ability.
*** These creatures retain any psionic abilities they had previously.
Spells Resembling Psionic Powers
Note: Magic items that perform these powers, or that duplicate psionic abilities, may be treated as spell functions resembling psionic operations.