Sam came into psychotherapy during a difficult period at work. He had started to feel as if he was stagnating in his role and it was getting him down. As he approached midlife he had reached a level of seniority that he had sought for years, but now he was starting to wonder whether this was it. He wasn’t sure exactly what the matter was: he didn’t feel especially depressed, just somehow stuck. It had taken him a long time to consider speaking to someone – what could they really do, in the absence of an obvious psychological disorder?

Psychotherapy occupies an increasingly central place in our culture. Just as we have become inclined to understand our struggles and our sadness under the heading of “mental health”, so too we have placed ever greater authority on psychotherapists to help us understand how we should deal with the problems life throws up. Even those without diagnoses of depression, anxiety or obsessive compulsive disorder increasingly seek therapeutic support, with a recent survey finding that around a third of the population have done so.

But psychotherapy is a diverse enterprise, with multiple competing schools of thought. You might have decided to start working with a therapist, but should you choose psychoanalysis, cognitive behavioural therapy, existential therapy or acceptance and commitment therapy? These different approaches come with their own terminology and ideas. They seem to have different convictions about human nature. Are we creatures who act on unconscious urges or according to cognitive schemas? You’d be forgiven for thinking there might be a right and wrong answer, and that you might make a terrible mistake depending on what style of therapy you choose.

Researchers have sometimes tried to get to the bottom of this issue using formal research trials, where competing models are tested against each other. By exploring which therapies best reduce distress (measured on numerical scales), the hope is that a “winner” can be found. As it turns out, though, different therapies tend to perform just about as well as each other (with one or two important caveats: if you have OCD you really need to seek good CBT). This is the so-called “Dodo bird verdict”, after the Alice in Wonderland character who declares “everybody has won and all must have prizes”. What matters more than theory are (among other things) a strong working alliance between therapist and patient, a deliberate process of setting goals, and a genuine capacity in the therapist for empathy.

Rather than thinking of some therapeutic approaches as fundamentally more correct in their analysis of what makes us tick, we might say instead that the various psychotherapeutic models each emphasise different aspects of our mental worlds. For the psychoanalyst, the point of therapy is to make the unconscious conscious. For the cognitive behavioural therapist, the point is to adjust distorted thought patterns. These tasks will be relevant for different people at different points. But what we might think of as the overall point of psychotherapy is to help us to think – in the richest sense of that word – about our lives, about who we are and what we want, and thereby to live more actively and more freely.

This framing takes away some of the mystique created by arcane technical jargon. You might believe in entities such as “superegos” or the concept of “transference,” or you might prefer talk of “cognitions” and “beliefs”, but you don’t have to choose. At the core of psychotherapy is a regular, time-limited process of one person meeting another and listening to their thoughts and concerns. “Thinking” here is not the same as rumination – rigid preoccupation suffused with guilt or anxiety. Rather, it means paying attention to what you desire and what you dread. It means noticing when you are behaving passively or inconsistently, and it means allowing yourself time to experience your emotions fully and respond to them in a way that is deliberate and considered.

At first glance, this understanding of therapy seems to question whether psychotherapeutic theory has any value at all. If all treatments are able to achieve similar results, what is the point of learning in depth about any one of them? Rather than binning their books, however, therapists should be reading from a wide variety of theoretical perspectives. Each may have something to contribute in a given context, or at a given time.

Equally, this is not a mandate for “anything goes” quackery. A professional therapist needs to learn how to manage their own emotional responses in the consulting room; they need to become practised at noticing when and how the patient is avoiding sensitive topics, and critically they need to learn what not to say. Psychotherapy is sometimes dismissed as nothing more than a sort of paid-for friendship, but there is more to it than that. Our friends support us and listen to us, but they don’t necessarily have the same commitment to paying careful attention and challenging our assumptions; friendships have an element of mutuality – sparing someone’s feelings, or mirroring them – that therapy may need to omit. At the same time, it is an active process; the therapist can try to foster thinking but cannot do it on behalf of the patient. It comes into its own when patients are trying to work something out, and are genuinely perplexed about their mind or relationships.

Sam, as it turned out, had lived much of his life without thinking especially hard about what he was up to. He had made choices, but had in large part followed a course set out for him by others. Now life was starting to throw up its inevitable problems: a declining parent, a rocky period in his marriage and the resulting slump in self-confidence. He could no longer work from the same script.

Through therapy, Sam engaged in the first conversation he’d ever really had about the choices he had made, and the vulnerabilities he had avoided thinking about. Therapy hadn’t simply alleviated an unpleasant feeling or symptom. It had led him to consider his values, his self and his assumptions. In other words, it prompted him to think closely about his life in a way that few other kinds of conversation could.

• Huw Green is a clinical psychologist and neuropsychologist at Addenbrooke’s hospital in Cambridge.

Further reading

In Therapy: The Unfolding Story by Susie Orbach (Profile, £11.99)

And How Does That Make You Feel? by Joshua Fletcher (Orion, £9.89)

The Examined Life: How We Lose and Find Ourselves by Stephen Grosz (Vintage, £10.99)