Final answer:
Research following Eysenck's study generally supports the effectiveness of psychotherapy, with therapies like cognitive-behavioral therapy showing high efficacy in treating psychological disorders.
Step-by-step explanation:
Since Eysenck's study, numerous studies have been conducted to look at the effectiveness of psychotherapy. These studies generally suggest that psychotherapy is an effective treatment for various psychological disorders. Influential theories such as those developed by Freud and Rogers, along with the cognitive-behavioral branch, have guided clinical practices over time. Studies have found that therapies like cognitive-behavioral therapy have a strong empirical basis and are highly effective. Moreover, psychotherapy is comparably effective to antidepressant medication in treating depression and anxiety disorders, according to a meta-analysis.