We provide a narrative review of the extensive evidence that supports the efficacy and effectiveness of psychological treatments, across the life span, for common mental health disorders. To this end, relying primarily on meta-analytic studies, we examine the effects of psychological treatments for depression, bipolar disorder, generalised anxiety disorder, social anxiety disorder, specific phobia, panic disorder, obsessive-compulsive disorder, and posttraumatic stress disorder. Based upon data from hundreds of studies and thousands of participants, there is substantial evidence for both the efficacy and effectiveness of specific forms of psychological intervention for these disorders. Moreover, for most disorders, the clinical impact of specific forms of psychological treatment has been found to be at least equal to that of medication. Accordingly, the research evidence strongly supports the use of a number of specific psychological treatments, most of which are cognitive-behavioural treatments, as first-line interventions for these commonly occurring mental disorders among youth, adults, and older adults.Keywords: treatment efficacy, treatment effectiveness, mood disorders, anxiety disordersResumeNous presentons une revue narrative des preuves approfondies qui confirment l'efficacite et l'utilite des traitements psychologiques, au cours des diverses etapes de la vie, pour les troubles de sante mentale courants. A cette fin, au moyen essentiellement de meta- analyses, nous examinons les effets des traitements psy- chologiques pour la depression, le trouble bipolaire, le trouble d'anxiete generalise, le trouble d'anxiete sociale, les phobies pre- cises, le trouble panique, le trouble obsessionnel-compulsif et le syndrome de stress post-traumatique. Selon les donnees tirees de centaines d'etudes regroupant des milliers de participants, il existe des preuves substantielles tant de l'efficacite que de l'utilite des interventions psychologiques precises pour ces troubles. En outre, pour la plupart, l'effet clinique de traitements psychologiques precis s'est revele au moins equivalent a celui de la medication. Ainsi, les resultats des recherches appuient fortement l'usage de certains traitements psychologiques precis, dont la plupart sont des therapies cognitivo-comportementales, en tant qu'intervention de premiere ligne pour ces troubles mentaux qui sont courants parmi les jeunes, les adultes et les aines.Mots-cles : efficacite d'un traitement, utilite d'un traitement, trou- bles de l'humeur, troubles anxieux.Based on the results of extensive research on the effects of psychological treatments, the American Psychological Association (2013) passed a resolution recognising the substantial clinical impact of psychotherapy. Although such a global statement about the positive effect of psychotherapy does reflect the general re- search findings, it glosses over the substantial variability evident in the psychological treatment research literature, including (a) not all treatments have been empirically evaluated, and (b) some treat- ments are more efficacious than others in the treatment of specific disorders (e.g., Siev & Chambless, 2007). Psychotherapies have been developed to address a broad range of mental health and health conditions, which makes it essential that consumers of the treatment literature have an awareness of the differences in the nature, strength, and scope of evidence supporting the various options available to treat a specific disorder or condition. In particular, it is critical for consumers of the research literature to be able to determine the forms of treatment that have been demon- strated to improve psychosocial functioning for those suffering from prevalent mental disorders. Such information is essential for clinicians delivering psychological treatments, for those develop- ing policies on first-line treatment options, and, of course, for those seeking treatment.In recent years, an important distinction has been emphasised in the treatment literature with respect to research focused on the outcome of psychological interventions. …