Synonyms for Have the brain:

• adj.

  •obsessed (adjective)
  • held,
  • eat sleep and breathe,
  • taken over,
  • seized,
  • Fiendish,
  • engrossed,
  • dominated,
  • hooked,
  • harassed,
  • overpowered,
  • infatuated,
  • wrapped up in,
  • haunted,
  • wound up with,
  • Into,
  • tormented,
  • really into,
  • dogged,
  • immersed in,
  • controlled,
  • Prepossessed,
  • bewitched,
  • gripped,
  • preoccupied,
  • bedeviled,
  • captivated,
  • beset,
  • up to here in,
  • possessed,
  • plagued,
  • fixated,
  • hung up on,
  • tied up,
  • troubled,
  • turned on.
  •preoccupied (adjective)
  • distracted,
  • hung up,
  • lost,
  • intent,
  • removed,
  • bugged,
  • bemused,
  • distrait,
  • daydreaming,
  • faraway,
  • engaged,
  • Immersed,
  • deep,
  • wrapped-up,
  • spellbound,
  • oblivious,
  • inconscient,
  • asleep,
  • lost in thought,
  • airheaded,
  • taken up,
  • absorbed,
  • woolgathering,
  • heedless,
  • Absent-minded,
  • abstracted,
  • absent,
  • spread out,
  • forgetful,
  • fascinated,
  • unaware,
  • Mooning,
  • moony,
  • obsessed,
  • rapt.

• n.

  •compulsion (noun)
  • hang-up,
  • preoccupation,
  • need,
  • duty,
  • urgency,
  • monkey,
  • force,
  • constraint,
  • have on the brain,
  • engrossment,
  • demand,
  • necessity,
  • driving,
  • prepossession,
  • urge,
  • drive,
  • pressure,
  • coercion,
  • exigency,
  • obsession,
  • tiger by the tail,
  • duress.

Antonyms for Have the brain:

• adj.

  • obsessed
    unconcerned, indifferent, disenchanted.
  • preoccupied
    disenthralled, uninterested, disinterested, unoccupied, bored, existing, thoughtful, observant.

• n.

  • compulsion
    independence, free will, license, liberty, freedom.