background: Psychosis is an illness characterised by alterations in thoughts and perceptions resulting in delusions and hallucinations. Psychosis is rare in adolescents but can have serious consequences. Antipsychotic medications are the mainstay treatment, and have been shown to be effective. However, there is emerging evidence on psychological interventions such as cognitive remediation therapy, psycho-education, family therapy and group psychotherapy that may be useful for adolescents with psychosis. objective: To assess the effects of various psychological interventions for adolescents with psychosis. methods: We searched the Cochrane Schizophrenia Group's study-based Register of Trials including clinical trials registries (latest, 8 March 2019). methods: All randomised controlled trials comparing various psychological interventions with treatment-as-usual or other psychological treatments for adolescents with psychosis. For analyses, we included trials meeting our inclusion criteria and reporting useable data. methods: We independently and reliably screened studies and we assessed risk of bias of the included studies. For dichotomous data, we calculated risk ratios (RRs) and 95% confidence intervals (CIs) on an intention-to-treat basis. For continuous data, we used mean differences (MDs) and the 95% CIs. We used a random-effects model for analyses. We created a 'Summary of findings' table using GRADE. results: The current review includes 7 studies (n = 319) assessing a heterogenous group of psychological interventions with variable risk of bias. Adverse events were not reported by any of the studies. None of the studies was sponsored by industry. Below, we summarise the main results from four of six comparisons, and the certainty of these results (based on GRADE). All scale scores are average endpoint scores. Cognitive Remediation Therapy (CRT) + Treatment-as-Usual (TAU) versus TAU Two studies compared adding CRT to participants' TAU with TAU alone. Global state (CGAS, high = good) was reported by one study. There was no clear difference between treatment groups (MD -4.90, 95% CI -11.05 to 1.25; participants = 50; studies = 1, very low-certainty). Mental state (PANSS, high = poor) was reported by one study. Scores were clearly lower in the TAU group (MD 8.30, 95% CI 0.46 to 16.14; participants = 50; studies = 1; very low-certainty). Clearly more participants in the CRT group showed improvement in cognitive functioning (Memory digit span test) compared to numbers showing improvement in the TAU group (1 study, n = 31, RR 0.58, 95% CI 0.37 to 0.89; very low-certainty). For global functioning (VABS, high = good), our analysis of reported scores showed no clear difference between treatment groups (MD 5.90, 95% CI -3.03 to 14.83; participants = 50; studies = 1; very low-certainty). The number of participants leaving the study early from each group was similar (RR 0.93, 95% CI 0.32 to 2.71; participants = 91; studies = 2; low-certainty). Group Psychosocial Therapy (GPT) + TAU versus TAU One study assessed the effects of adding GPT to participants' usual medication. Global state scores (CGAS, high = good) were clearly higher in the GPT group (MD 5.10, 95% CI 1.35 to 8.85; participants = 56; studies = 1; very low-certainty) but there was little or no clear difference between groups for mental state scores (PANSS, high = poor, MD -4.10, 95% CI -8.28 to 0.08; participants = 56; studies = 1, very low-certainty) and no clear difference between groups for numbers of participants leaving the study early (RR 0.43, 95% CI 0.15 to 1.28; participants = 56; studies = 1; very low-certainty). Cognitive Remediation Programme (CRP) + Psychoeducational Treatment Programme (PTP) versus PTP One study assessed the effects of combining two types psychological interventions (CRP + PTP) with PTP alone. Global state scores (GAS, high = good) were not clearly different (MD 1.60, 95% CI -6.48 to 9.68; participants = 25; studies = 1; very low-certainty), as were mental state scores (BPRS total, high = poor, MD -5.40, 95% CI -16.42 to 5.62; participants = 24; studies = 1; very low-certainty), and cognitive functioning scores (SPAN-12, high = good, MD 2.40, 95% CI -2.67 to 7.47; participants = 25; studies = 1; very low-certainty). Psychoeducational (PE) + Multifamily Treatment (MFT) Versus Nonstructured Group Therapy (NSGT, all long-term) One study compared (PE + MFT) with NSGT. Analysis of reported global state scores (CGAS, high = good, MD 3.38, 95% CI -4.87 to 11.63; participants = 49; studies = 1; very low-certainty) and mental state scores (PANSS total, high = poor, MD -8.23, 95% CI -17.51 to 1.05; participants = 49; studies = 1; very low-certainty) showed no clear differences. The number of participants needing hospital admission (RR 0.84, 95% CI 0.36 to 1.96; participants = 49; studies = 1) and the number of participants leaving the study early from each group were also similar (RR 0.52, 95% CI 0.10 to 2.60; participants = 55; studies = 1; low-certainty). conclusions: Most of our estimates of effect for our main outcomes are equivocal. An effect is suggested for only four outcomes in the SOF tables presented. Compared to TAU, CRT may have a positive effect on cognitive functioning, however the same study reports data suggesting TAU may have positive effect on mental state. Another study comparing GPT with TAU reports data suggesting GPT may have a positive effect on global state. However, the estimate of effects for all the main outcomes in our review should be viewed with considerable caution as they are based on data from a small number of studies with variable risk of bias. Further data could change these results and larger and better quality studies are needed before any firm conclusions regarding the effects of psychological interventions for adolescents with psychosis can be made.