I have been asked about the difference between negative spirits as different from negative thought forms. My conclusions are a result of reading and personal experience.  The following two books provide the published information:-

Psychic Self Defence by Dion Fortune 1998 Thorsons press.   -  Chapter 4 :- Projection of the Etheric Body.  Here she describes how she accidentally made a negative thought form and how she managed to deal with it.

Man Visible and Invisible by C.W. Leadbeater 1974  Adyar press.  Chapter XVIII  :- Sudden Emotions.  Here Leadbeater writes about the creation of positive thought forms.

To follow on from the published works, my personal experience is that thought forms are filled with the energy and intent of their originator. 

Yes thought forms are projections of thought energy, but they also develop a kind of existence of their own, having at their core the original intent of the person who created them.  Long established thought forms may even have a kind of personality, limited to the original intent “written” into it.  They can pass from one person to another - for good or ill.  A positive thought form may grow as it is reacted to and acted on and then projected to another person – i.e. when we feel good we send love and caring to others.  Conversely a negative thought form may grow as it is reacted to and acted upon and projected to another person or situation.  Remember the “kick the cat syndrome”?  So many people project their negative emotions onto someone else, often to a less powerful person or as last resort the poor old cat.

In a healing context – A negative soul can be healed of it’s afflictions with powerful light and love.  A negative thought form that is merely energy and substance with a negative polarity or intent is dissipated when sent powerful light and love.  When dealing with difficult psychic phenomena I have found it to be very important to know the difference and to act accordingly.  All souls who have fallen into negative functioning can be healed and restored.  The negative thought forms, however powerful they appear to be cannot, instead the light provided can purify them and change the energy from negative to positive and the substance from ugliness to beauty. 

In the realm of energy and thought forms we as souls are all creators of the world we exist in.  The thought forms or energies that we project into the world are a direct result of our mental and emotional state at any given time.

Lastly I’d like to provide something to think about in relation to personal responsibility with a couple of quotes from Ted Andrews in his excellent book, Psychic Protection, (Dragonhawk 1998) :-

pp: 95  “Ultimately, we are karmically responsible for all thought forms we create.”

and

pp: 98 “The proper use of thought power is to do no harm to any creature.”

Thank you Ted