The dangers of raising kundalini without proper guidance. - Kristo Gabriel

"The seeker who dares to awaken the kundalini power without the grace and guidance of a guru might become insane, succumb to disease, or even die. This is because he does not possess the necessary knowledge, steadiness of mind, or patience required for this difficult undertaking. Many seekers are found wandering here and there in search of a guru who will awaken their kundalini ...
Although thousands may claim that they know kundalini and that their kundalini is awakened, it is doubtful if even one of them really has such knowledge or experience. 
To awaken the kundalini power is one thing, but to make it move upward into the passage of the sushumna is something else. In the beginning, as the kundalini is awakened, the seeker feels a lot enthousiasm. But as he advances in meditation, he begins to encounter various menaces of kundalini. Only one with a great courage can cope with the menaces; it is simply not possible for all to do so."

- Swami Kripalvananda, Science of meditation  -

The aspirant, therefore, has three things to do:

1. Purity, discipline and transmute his threefold lower nature
2. Develop knowledge of himself, and equip his mental body; build the causal body (soul) by good deeds and thoughts.
   
3. Serve his race in utter self-abnegation.
   

Source : Alice Bailey, The danger of arousing kundalini.

Two works by a brilliant psychiatrist with the name Stanislav Grof are helpful for people in crisis due to a sudden kundalini awakening (every psychologist and psychiatrist should study these works) :

The Stormy Search for the Self A Guide to Personal Growth Through Transformational Crisis

Spiritual Emergency When Personal Transformation Becomes a Crisis