This study aims to examine the immediate and longer-term effectiveness of a group cognitive behavioral therapy intervention (GCBT) in reducing internalizing and externalizing symptoms in children treated for mixed psychiatric disorders in naturalistic clinical settings. Further, the effectiveness of GCBT is compared to a treatment-as-usual condition (TAU). Within this study, it is hypothesized that children with mixed psychiatric disorders will exhibit improvements in parent-rated internalizing problem behavior and parent- and teacher-rated externalizing problem behavior following GCBT.

Inclusion Criteria:

• Helsinki University Hospital child psychiatric outpatient clinic patients with symptoms of anxiety or depression, deficiencies in emotional and behavioral skills impairing functioning, and sufficient social and cognitive skills to participate in group work.

Exclusion Criteria:

• Helsinki University Hospital child psychiatric outpatient clinic patients with excessive physical aggression, excessive physical restlessness to enable skill training, or whose severity of psychiatric symptoms required individual psychotherapy (e.g., acute suicidality or psychosis).