Can the Suggestion and Mass Suggestion spells alter feelings?

Question

In 5e D&D, the Suggestion-style spells can suggest a path of action via charm-like forces. This suggests (ha ha) that it alters the thought and feeling process of the target. Obviously the ramifications for life-coaching are astounding, but let us put that aside for the moment.

Much of society &/or culture spends a vast amount on chemicals that do little more than alter state of being (alcohol, cigarettes, coffee are only the socially-expected 'tip of the iceberg'). Indeed, 5e D&D has spells that change the minds of people - but it does not explicitly explain how this changes the impacted person's feelings. For example, a depressed person experiencing Charm is still depressed, but they feel a bit more friendly towards a specific person should they fail their saving throw.

If there is a RAW explanation or example for how (Mass) Suggestion spells &/or effects change feelings beyond thought-action mechanics it changes how the spell impacts the game. Imagine marketing this suggestion-magic as a drug, a valuable resource with NO withdrawal - and minimal risk of addiction. An entire industry would logically exist for any bard, wizard or sorcerer with access to this second level spell.

What would be even more interesting is if this feeling-manipulation could be used to solve psychological barriers. Imagine telling a target 'You will figure out the inner-dialogue on how to be confident... and free of anxiety... in the next two to eight hours.' If psychological states can be over-suggested (meta-suggested?) then this suggestion-impact could even allow a fresh saving throw for all mind-impacting spells.

• Fear &/ or frightened condition: 'You are NOT afraid! Your course of action is to stop trembling and function normally.'

• Charmed &/or effects: 'You do not find that vampire charming.'

• Possession: 'You will cast out that ghost - they are not you! Resist!'

• Song of Harpies: 'This is not your kind of music, you prefer violin concertos. Do not listen to her!'

At higher levels of Mass Suggestion this would function without concentration. If this mental suggestion-force were allowed it would provide resistance or even immunity to specific magic &/or spells pending the wording of the original (suggest) spell.

In short: Can Suggestion-style magic create specific states of being whilst suggesting an action? Is feeling a state of being considered an action? If so, does this extend into saving throws and resistances against other mind-controlling magic?

Answer 1

Suggestion can't beat condition mechanics

In a general sense if someone is frightened of heights or charmed by a handsome man, you could use Suggestion to prevent that from happening. Would they still feel just as afraid but magically have the strength to face their fear? Good question, I don't have an answer for that, but they may certainly be able to "stop trembling and function normally".

However neither of those things would actually apply the Frightened or Charmed conditions. There is a distinction between being frightened in the normal sense, and being under the effect of the mechanical Frightened condition.

Saving throws represent the target's ability to resist an effect

Remember that usually there is some effect in the game world causing the condition, such as Fear or Charm Person. Your ability to "snap out of it" is the saving throw. The target of Suggestion performs the task "to the best of its ability". If the target fails the saving throw then that is the best of their ability.

DM rulings

In 5e the DM is given a lot of latitude and power when deciding what happens in specific circumstances. It would be entirely reasonable to rule that the target which was suggested "You are NOT afraid!" has Advantage on checks against fear.

Answer 2

Suggestion does not alter the target's feelings

Suggestion and mass suggestion both state:

You suggest a course of activity (limited to a sentence or two) and magically influence a creature you can see within range that can hear and understand you. [...] The suggestion must be worded in such a manner as to make the course of action sound reasonable. [...] it pursues the course of action you described to the best of its ability.

In short, suggestion enforces best-effort on a reasonable activity, but it doesn't alter the target beyond that, it doesn't grant new abilities, nor does it alter feelings. Hence, your ideas as presented don't work, because they are all attempts to use suggestion to grant a new ability to the target in the guise of altering feelings.

Consider for example the suggestion "become drunk" targeting a human. A human is incapable of spontaneously becoming drunk and suggestion does not alter this. This means that the target will do its best to acquire and drink alcohol until drunk. This example makes it very clear that suggestion does not alter the target's ability to complete the activity and that said activity can fail.

On the other hand, consider your examples: "you will figure out the inner-dialogue on how to be confident... and free of anxiety... in the next two to eight hours" is a prediction, while "You do not find that vampire charming" is an (inaccurate) description of the present. Predictions and descriptions are not activities so they are not valid sentences for suggestion.
Sure, you can infer activities from those predictions and descriptions, but predictions and descriptions disregard of the target's ability to complete the inferred activity and that makes them fundamentally incompatible with suggestion. When properly worded, such as "think of stuff that makes you confident" and "clear your mind of charms" respectively, they depend on the target's ability and cannot guarantee success, just like "become drunk".

You might also assume that your examples are possible, easy, or devoid of external interference because they are merely mental, but that is not the case. For example: "think of stuff that makes you confident" could be difficult if a target has poor introspection or if someone interferes with a endless stream of insults; "clear your mind of charms" is an impossible activity if the target doesn't have the ability to end the condition, such as the spell calm emotions, the monk's Stillness of Mind feature, an action specified by charming effect, etc.