Youths with severe and persistent irritability have a particularly high rate of school failures and learning difficulties. The aim of this study was to determine whether inpatient adolescents with Disruptive Mood Dysregulation Disorder (DMDD) have more motor and/or language impairments compared to patients with other psychiatric disorders. A retrospective chart review of all consecutive cases admitted in two adolescent inpatient units between January 2017 and December 2018 was conducted (N = 191). All patients received multi-disciplinary clinical and developmental assessments. For a subtest of subjects, additional standardized tests were used to document motor and language impairments. In this clinical chart 53 adolescents with a DMDD (mean age 13.6 ± 1.5, min 12, max 16, 70% males) were compared to patients with a major depressive disorder (MDD, n = 64, mean age 15.3 ± 1.6, 52% males) and patients with a non-mood disorder (NMD, n = 61, mean age 14.4 ± 1.55, 59% males). Among inpatients with DMDD, 71% had an associated motor and/or language disorder, with combined forms in around two-thirds of cases. Compared to youths with MDD, participants with DMDD were more likely to have an associated developmental coordination disorder (67% vs. 22%, OR = 4.7) and a written language disorder (35% vs. 10%, OR = 4.6). While 31% of inpatients with DMDD had an associated communication/oral language disorder, this rate was not statistically different from those observed in the MDD group (11%, OR = 3.2). The frequencies of motor and language impairments were not statistically different between participants in the DMDD group and in the NMD group. The high rate of motor and written language disorders found in DMDD patients may partly account for their academic difficulties. Such finding, if confirmed, supports systematic screening of motor and written language impairments in youths with chronic irritability and suggests remediation potential.