Although all neurosis is, for Adler, a matter of insufficient social interest, he did note that three types could be distinguished based on the different levels of energy they involved:
The first is the ruling type. They are, from childhood on, characterized by a tendency to be rather aggressive and dominant over others. Their energy — the strength of their striving after personal power — is so great that they tend to push over anything or anybody who gets in their way. The most energetic of them are bullies and sadists; somewhat less energetic ones hurt others by hurting themselves, and include alcoholics, drug addicts, and suicides.
The second is the leaning type. They are sensitive people who have developed a shell around themselves which protects them, but they must rely on others to carry them through life’s difficulties. They have low energy levels and so become dependent. When overwhelmed, they develop what we typically think of as neurotic symptoms: phobias, obsessions and compulsions, general anxiety, hysteria, amnesias, and so on, depending on individual details of their lifestyle.
The third type is the avoiding type. These have the lowest levels of energy and only survive by essentially avoiding life — especially other people. When pushed to the limits, they tend to become psychotic, retreating finally into their own personal worlds.
There is a fourth type as well: the socially useful type. This is the healthy person, one who has both social interest and energy. Note that without energy, you can’t really have social interest, since you wouldn’t be able to actually do anything for anyone!
Adler noted that his four types looked very much like the four types proposed by the ancient Greeks. They, too, noticed that some people are always sad, others always angry, and so on. But they attributed these temperaments (from the same root as temperature) to the relative presence of four bodily fluids called humors.
If you had too much yellow bile, you would be choleric (hot and dry) and angry all the time. The choleric is, roughly, the ruling type.
If you had too much phlegm, you would be phlegmatic (cold and wet) and be sluggish. This is roughly the leaning type.
If you had too much black bile — and we don’t know what the Greeks were referring to here — you would be melancholy (cold and dry) and tend to be sad constantly. This is roughly the avoiding type.
And, if you had a lot of blood relative to the other humors, you be in a good humor, sanguine (warm and moist). This naturally cheerful and friendly person represents the socially useful type.
One word of warning about Adler’s types: Adler believed very strongly that each person is a unique individual with his or her own unique lifestyle. The idea of types is, for him, only a heuristic device, meaning a useful fiction, not an absolute reality!