Sounds like it could be the Dark Visions Trilogy, written by L.J. Smith.
The three books in the series are The Strange Power (1994), The Possessed (1995), and The Passion (1995), though they were also published as a single volume (aka an omnibus) in 2009. According to the wiki, the authot is writing a sequel to the series titled Blindsight.
Basic plot summary
The story follows the protagonist, Kaitlyn Fairchild, as she attends,
uncovers a plot, and ultimately defeats the Zetes Institute, a place
where she went to learn about her own psychic powers. Kait and the
four other psychics at the live-in Zetes Institute are the most
powerful psychics in the country in their age group. They come from
all areas of the U.S. and become best of friends.
The teens:
Kaitlyn Brady Fairchild, known as Kait, is the 17 year old protagonist of the series. Her psychic talent is that she (usually subconsciously) creates drawings that are premonitions. Her inability to understand the drawings until too late drives her to attend the Zetes Institute.
Rob Kessler (also seventeen) is a North Carolina native and another attendee of the Zetes Institute. His power is the ability to heal by manipulating life energy
Gabriel Wolfe (also seventeen) is the ambiguous character that eventually joins the light side. He comes to the Zetes Institute from jail, having previously killed by accident and in self-defense. He is a telepath, and when he uses his power on minds that are weaker than his, he drains those people of their life energy.
Anna Eva Whiteraven (also seventeen) is the only other girl at the Zetes Institute and is from Washington State. She is Native American and described as having long black hair. She is very peaceful and gentle girl who becomes Kait's roommate at the Institute. Her psychic abilities allow her to communicate with animals and control them.
Lewis Chao (also seventeen) is from San Francisco and is the last of the group at the Zetes Institute. He is Asian-American and described to be friendly and obsessed with technology. He has the ability of psychokinesis, the ability to move (small) objects with his mind; later he uses his abilities to jam radio frequencies, set off telephones, even open hidden doors.
The Evil Plot:
From Strange Power (Book 1):
While at the Institute, they are tested on their psychic abilities,
but a mysterious man warns Kaitlyn that the Institute is dangerous,
and even the sullen housekeeper Marisol warns them to get out as soon
as possible, after which she goes into coma. The psychics become
suspicious and begin to believe the warnings about the Institute. They
investigate and find a secret passageway, which contains plans to turn
them into psychic weapons to sell to major corporations, and a file
about Project Black Lightning, a previous project in which other
psychics were tested upon and 'terminated'. The teens almost get
caught by the head of the Institute, Mr. Zetes, and Gabriel locks the
five of them into a psychic link to save them. The link allows them to
'hear' each other's thoughts and communicate, but they cannot get rid
of it afterwards so they try to find a way to break the link, but
discover that the only way is for one of them to die. Eventually, Mr.
Zetes talks to Gabriel and invites him to his mansion to discuss his
future, as he believes Gabriel is ready to join him in his plans to
create psychic weapons. Kaitlyn overhears the conversation and offers
to join too, so she can find out the what is really happening. At the
mansion, Mr. Zetes shows them a giant crystal that will make them
powerful weapons by amplifying their psychic powers but he admits that
it can warp minds and make them evil, as he found out with 'Project
Black Lightning'
About the villain:
Emmanuel Zetes is the villain of the story. He is very wealthy and
founded the Zetes Institute for research on psychic phenomena.
However, it is revealed that the Institute is actually preparing
psychics to perform as a special for-hire task force for criminal
activities. He is the owner of a "firestone" or "great crystal", which
can store and enhance psychic energy.
Locked and bound in a soundproof room
From The Passion (Book 3):
Kaitlyn is eventually caught by Mr Zetes when she cracks the code for
the location of the crystal, and he puts her in an isolation tank,
where he hopes she will be driven to insanity. Gabriel becomes worried
about Kaitlyn when he can no longer feel her presence in the psychic
link and he reaches out for her with his telepathy. He helps her
preserve her mind by showing her memories and communicating with her,
and they both confess their true depths of feelings for each other.
When Mr Zetes takes Kaitlyn out the isolation tank, he realises his
plan has not worked and he takes Kaitlyn to the crystal to destroy her
mind. Rob, Anna, Lewis and Tamsin from the fellowship of the crystal,
turn up to rescue them, and they succeed in destroying the crystal and
Mr Zetes when Gabriel unites the shard with the evil crystal. When the
crystal is shattered, Joyce's mind and the other psychic's minds are
returned to them, and they realise the mistakes they made in joining
Mr Zetes.
