In light of the information extracted from the included articles, we have divided the results into different key aspects that include the characteristics of the migrant population in the selected studies, the differences found by migrant background in emotional and relational problems, and the factors affecting the latter.

Characteristics of the migrant population in the included studiesDefinition of ‘migrant’

There is no unified definition of ‘migrant’, not even of first- and second-generation migrant. Therefore, it is not surprising that there is no consensual definition of a native person in the migration literature either. The studies included in the present paper are no exception in this regard. While five out of 36 studies hold the exact definition of first-generation migrant, second-generation migrant and native [3, 16, 26,27,28], the rest of the studies either hold slightly different definitions of these terms or do not define what they consider to be a migrant or a native.

Some studies only provide their generic definition of migrant without differentiating between generations. For instance, two studies focus on nationality, defining those who have a different nationality from the host country as migrants [29, 30]. Another two studies focus on the parents’ origin, meaning that either one or both parents should be born abroad for an adolescent to be considered a migrant [31, 32]. As they do not point to where the adolescent was born, this definition could include first- and second-generation migrants according to our definition. Finally, another two studies consider that an adolescent can be defined as a migrant if they and both parents were born abroad, which is what we consider a first-generation migrant, according to our definition [33, 34].

Regarding the definitions of first-generation migrants, all included studies that provide a definition align with ours [3, 16, 26,27,28, 35,36,37,38,39,40]. However, three of them specifically mention that the adolescent and at least one parent should be foreign-born [41,42,43]. While we automatically consider that an adolescent is a first-generation migrant if he or she was born abroad, these three studies also add the condition that at least one parent should be born abroad as well. Technically, the adolescents included in this category would all be the same, but these three articles go a step further and provide specific information regarding both parents’ origins.

Second-generation migrants are also defined by almost all included studies which evaluate their results for this profile in the same way as our definition, meaning that the adolescents are native-born and at least one of the parents is born abroad [3, 16, 26, 28, 36, 42, 43]. Nevertheless, five studies add to their definition that both parents have to be born abroad [35, 37,38,39,40]. Finally, studies also differ in their definition of native adolescents. Most papers that define a native adolescent coincide with our definition [3, 16, 26,27,28, 31, 32, 35, 39, 42, 43]. However, four studies considered a child with at least one native parent as a native [36,37,38, 40], while that would fit our definition of a second-generation migrant. Only one study focuses on nationality to define the participant’s background [29].

While all included studies provide results for migrant adolescents compared to native adolescents, only a few focus on specific migrant profiles. Five studies provide evidence of emotional and relational problems in first- and second-generation migrant adolescents, comparing them to their native peers [4, 35,36,37, 43]. Two studies compare refugee adolescents to their native peers [33, 34]. Finally, only one study targets unaccompanied minors and compares them to their non-migrant peers [44].

Countries of destination and countries of origin of participants with a migrant background

This study focuses on the emotional and relational problems of adolescents with and without a migrant background in Europe. Nevertheless, the selected papers solely represent 11 European countries. Seven studies focus on Italy [27, 37,38,39, 42, 44, 45], five in the Netherlands [28, 31, 32, 45, 46], four in Germany [32, 47,48,49] and Spain [29, 50,51,52], three in Austria [3, 36, 53], Sweden [16, 35, 40] and Turkey [33, 34, 54], two in Greece [4, 55], Portugal [51, 52] and Switzerland [30, 56] and only one in Norway [26] and in several European countries [43].

Surprisingly, of the 36 included studies, seven provide specific information about the countries of origin of the migrant-background adolescents, enabling comparisons by the origin of the participants. Dutch adolescents are the population that got the most compared by the selected studies, including non-Western adolescents [31], Moroccan adolescents [28], Surinamese, Turkish and Moroccan Dutch adolescents [45, 46]. Germans are compared to Asians [47] and other European adolescents [48]. Italian adolescents are compared to Eastern European, non-Western non-European and Western European migrant adolescents [42, 57]. Finally, Spaniards are compared to Latin-American migrant adolescents [50].

Differences found by migrant background in emotional problems

To verify if the included studies found results in line with our hypothesis, we analysed whether they found clear evidence that adolescents with a migrant background portrayed more emotional problems than their native peers, fewer problems or no significant differences between both groups. Emotional problems mainly refer to depression, anxiety and related emotional symptoms, including suicidal thoughts. In this analysis, we also highlighted the specific origin of the migrant-background adolescents if this sample was composed of at least 100 adolescents, enabling significant comparisons and extracting conclusions. As many studies did not describe the background of the migrant adolescents in their sample or this group was too small, we provide this information in a few cases.

A total of 10 papers found results that aligned with the hypothesis, as portrayed in Table 1. Seven of them measured the differences between the two groups in anxiety problems and symptomatology [33, 36, 44, 47, 49, 53, 54]. Only one of them included refugee adolescents [33], another one included unaccompanied migrant children [44], and another one measured social anxiety and differentiated it between first and second generation, finding that the first generation showed more anxiety symptoms, followed by the second-generation adolescents and finally by adolescents without a migrant background [36]. Nine papers which concentrated on depression and depressive symptomatology found results that coincided with the hypothesis, providing evidence that having a migrant status was associated with higher depression scores [3, 30, 33, 36, 44,