Spiritual direction is a Christian discipline which shares some things in common with traditional counseling, but opens up more specifically Christian approaches and goals. While counseling is typically problem-oriented, spiritual direction is geared towards spiritual growth for anyone seeking a deeper or more active devotion and service to God.
Have you ever thought about the relationship between the counselor and the client in typical counseling? Let's say you start with a client who is basically struggling to relate to people in a normal and healthy way. Then you approach the problem by adding a key relationship -- that with the psychologist -- that is not in any sense a typical relationship. It is one-sided: the client has the problems and comes for help, the counselor keeps a professional distance. The client reveals secrets and gets vulnerable, the counselor hides behind a professional mask. Whatever that counselor/client relationship may be, it is not a friendship. It does not give the other person experience relating to people in a normal way; it does not build ties of friendship or fellowship. Because of that, it may not actually be what that person needs the most. It may even be a co-dependent sort of relationship. The client can alleviate his need for someone to trust and someone to talk to; the counselor meanwhile can be needed and can be an important part of someone else's life without the risk or the vulnerability of showing his or her own faults. There is a risk that counseling may deepen the habit of imbalanced, one-sided or needy relationships for the person seeking help.
In reading some of the literature on spiritual direction, I have kept an eye in particular on the types of relationships involved. I think it is a fair question whether "counselor/client" is a relationship on a Christian model. I am not saying that Christians can't make good use of a counselor/client relationship; I am saying that a traditional counselor/client relationship is less than it could be if counseling were approached from a thoroughly Christian model. On a Christian model, "one-sided relationship" is a contradiction in terms. I think there's a possibility for spiritual direction to be more along the lines discipleship, mentorship or even spiritual friendship. While counseling could be a help to some other area of life from which counseling and the counselor are safely removed, discipleship or spiritual friendship could itself be a part of that better life which it was helping to build.
If the goal of counseling is often to resolve certain problems, the goal of spiritual direction would be to build a Christian life. The relationship with the psychologist is meant to be outgrown when the client gains a certain level of health. There is a risk that counseling is at best a throw-away relationship, and at worst an embarrassed secret or a stigmatized relationship that in the long run could weaken a person's self-confidence. The relationship with a spiritual director might change from mentor to friend, but would deepen rather than being abandoned as each person grows in maturity.