Yes, you should be cautious about psychotherapy. Therapy asks a big investment of time and money, it isn't guaranteed to work, and it may ask you to question some of your long-held views about life. But surprisingly, you may have more in common with therapists than you imagined. Any well-trained therapist is probably just as skeptical as you: compassionately skeptical about the stories people tell themselves about who they are, about the way they present themselves, and about how they see the world.
So, your healthy skepticism would be welcomed and valued in therapy.
I understand skepticism in its best form to be a search for truth, even if it limits what we can know for certain. Psychotherapy is, in its best form, the search for truth about who we are and how to live that truth.
This has also been true of the development of therapy: we've had to search for the truth about how best to practice it. We've been refining our ways for over a hundred years, thanks in part to folks who've helped us question our theories and techniques, chucking the stuff that doesn't work and integrating the stuff that does. In fact I'd say that healthy skepticism has been an inherent part of the development of therapy, in addition to being an important part of its everyday practice.
Thank God for skeptics. You've helped us to clean up our act, sharpen our focus, and avoid investing in such scams as bloodletting, leeches, and those crazy, dangerous electronic devices they put into people's chest that couldn't possibly work called pacemakers. Catch my drift? You guys offer a critical perspective that can be profoundly important to the world, but destructive if applied indiscriminately. You may miss the benefits of your rigorous thinking if you stay on the sidelines all the time.
You might also be skeptical about whether therapy could be helpful to you personally. The way we sometimes present it, it might sound to you as if therapy were only for people who have been abused, traumatized or largely disabled by mental illness. Yes, therapy can help those, but it also works for those who've developed emotional callouses from the routine and cruelty of everyday life, for those who struggle with trusting that anyone or anything could help them, and for those whose strength is driving them crazy.
It's clear that therapy works for most people. Yes, there are outliers for whom it doesn't work. My hope is that we can help many of these by explaining what it means to "work on it in therapy" (see my book), so they can become equal partners in the process, and so that they won't wander aimlessly.
One reason that some people are skeptical about therapy is that it is hard to believe that they could walk into a room and spill their darkest secrets to someone they've never met before. And how could you trust someone who's making money doing this? Once again, it's wise to be cautious, but not so wise to be hopeless. While some people feel ready to dive in immediately, for many trust is developed gradually, and in all cases it must be earned by the therapist gradually. The process of developing confidence in a therapist can be beneficial in itself--if it's done consciously.
It's true that there are no guarantees that a particular therapist can be helpful to you, or that any therapist could be helpful to you. But since when is that a good reason not to try something? Certainty is a good standard for engineering, science, and criminal justice, but not for personal action.
Skeptics can benefit a great deal from therapy. Taken too far, skepticism can isolate and depress. And therapy is pretty good at helping with those issues. But my greater concern is that skeptics can become cynics, and cynics are harder to help because once they turn the corner into persistent dismissiveness, it's much more difficult for them to let anyone in.
One last point: Therapy is sometimes portrayed as a selfish and indulgent undertaking. If that's your concern, rest easy and find yourself a good therapist. There are many ways to help make the world a better place and therapy is one of them. From burnt-out activists, to those who would like to be a little more kind and compassionate, and a little less critical and angry, those who are helped by therapy can help the world, too. Therapy ideally sends us off better prepared to do our personal part for the world, whatever that may be. Including skepticism.