The main result of this longitudinal study was that psychological distress decreased from the end of the study programs until 3 years into the participants’ subsequent professional lives. Thus, our findings indirectly support the assumptions about higher levels of mental problems among students. Factors important for reduced psychological distress differed between the groups, but one factor, the current experience of quality of life, contributed to lower psychological distress with a moderate to large ES in all analyses.

The findings in this study are in line with previous studies showing that the transition from study to work is associated with better mental health in most student groups, independent of profession and gender [22, 24]. They are also in line with Harvey et al.’s review of the evidence-based literature suggesting mentally healthy workplaces [25]. However, we were interested in gaining a better understanding of the known tendency for reduced psychological distress from study to work. Therefore, we examined the three different groups with different factors associated with mental health 3 years into their professional lives. One factor of importance was the level of psychological distress when finishing the study. This had a significant impact on subsequent psychological distress among the healthcare professionals and teachers, but not among the social workers. However, the variance explained by the GHQ-12 Likert score as a student was modest, indicating that this factor alone is insufficient for explaining subsequent psychological distress.

Demand, control, and support are all factors defined as key work characteristics associated with both positive and negative outcomes [41]. Positive outcomes include motivation and learning, whereas negative outcomes include illness and strain, such as psychological distress. In a work context, demand can be understood as psychological, physical, cognitive and organizational constraints, work load, work environment, and pressure, not least of which is time pressure [26, 42]. Individuals who experience excessive job demands may feel like losing their personal resources and the capacity to cope with the demands. Demands may be stressful due to a feeling of not having the time or ability to do the tasks as expected. On the other hand, job control is one’s own control over tasks and is defined as the opportunity for decision authority or autonomy in work [41]. According to Bakker and Demerouti [43], job control can be a resource that allows the individual to deal with the work demands. Social support is an interaction between the employee and his or her supervisor and co-workers and is valuable according to task assistance, access to information, and social companionship. This is also called the employee’s social capital [41]. Such support may be experienced as a job resource [43].

In our study sample, higher levels of job demand had a significant impact on psychological distress. When dividing the sample into the three groups, demand was associated with a higher level of psychological distress among the participants in the healthcare and social work groups. An explanation for this may be that employees in health care and social work have a heavy workload related to their clients’ mental and physical health and well-being. In addition, the time they have available for each patient or client is limited. It is reasonable to assume that the association between job demand and higher psychological distress in these two groups may be due to an experience with the potentially detrimental consequences of a high workload and time pressure in these professional fields. In anticipation of their potentially harmful consequences for clients, high job demands may give rise to feelings of ineptness, reduced coping, and higher distress levels.

Such thinking is in line with Lazarus and Folkman [44], who demonstrated that perceived coping resources contribute to the individual’s stressor perception. Previous studies underscore that workplace demands and experiencing a loss of resources may produce psychological distress. In turn, such distress may reduce the ability to meet the demands and result in loss of energy and reduced health [43, 45, 46]. Although there may be high levels of job demand in a classroom when working with children and adolescents, in addition to all preparations and follow-ups, an explanation for why demand did not significantly impact psychological distress in the teacher group is needed. As previously noted, the consequences of not meeting the demands in every situation may not be as severe as when working with vulnerable clients. Compared to the health care professionals, teachers’ ‘clients’ are primarily healthy children, whereas the health care group is confronted with life and death. In addition, the workload may be experienced differently by the young teachers compared to their counterparts in healthcare and social work.

Only in the teacher group, higher levels of control were significantly associated with reduced psychological distress. As described above, job control is characterized by the experience of having control over tasks, as well as an opportunity to exercise decision authority and autonomy in the work. Therefore, the results may indicate that, for the teachers, greater opportunities to think of alternative solutions and the ability to make spontaneous decisions and use different pedagogy are important for their distress levels. As such, job control can be experienced as a resource that allows the teacher to deal with the demands related to working as a teacher.

In the health care group, support was associated with better psychological health, whereas the association was the opposite in the teacher group. In health care, there is a tradition that seniors supervise and support young colleagues, regardless of how and when the demands are (too) heavy. Well-functioning systematic support may prevent the development of psychological ill health and generally contribute to higher levels of social capital. In addition, more confidence, as part of the professional role, was significantly associated with better mental health among healthcare workers. Regular supervision, being part of a hierarchical system with senior colleagues, and often working together with co-workers may contribute to explaining these results. In addition, both the health care professions and social worker traditions normally apply supervision both during education and in the first years of professional work. Klette and Smeby [47] and Scheerens [48] have reported in their research on teachers that collegial feedback for teachers is rare. It may be that the pattern of support in teaching is less systematic and less targeted to solving challenges in the workplace and more tailored towards individuals with expressed needs at the personal level. If this were the case, more support would be reported by those experiencing higher levels of distress.

Compared to the other two groups, the teachers exhibited a smaller reduction of psychological distress from the end of their study to 3 years after starting as a young employee. However, a significant difference was only found for the healthcare group. The reasons for these differences may be related to the above arguments according to job demand, control, and support.

Better mental health as measured by the GHQ-12 was associated with experiencing a higher quality of life in all three groups. This finding seems to be in line with the theoretical expectation that good mental health as measured by the GHQ-12 is strongly associated with good quality of life, and vice versa. For example, Næss et al. [49] defined quality of life as mental well-being based on the person’s cognitive and affective experiences and if these are positive or negative. In principle, GHQ 12 measures both positive and negative mental health.

Næss et al. [49] described global quality of life to include an individual’s satisfaction, happiness, meaning, and realization of goals in their own lives, and it is the individual’s subjective opinion that is requested. According to Næss et al. [49], it is the individual’s own opinion about his or her life that is important. She emphasized that mental well-being is related to happiness, whereas satisfaction is associated with the individual’s personal appraisals. Her definition includes both cognitive and affective aspects, including thoughts, appraisals, feelings, and emotions. Being satisfied with life as a whole seems to cause good mental health. On the other hand, it may be that good mental health improves the quality of life and experience of having a good life. In general, demographic variables had a small impact on psychological distress. This finding is line with previous research among young professional workers [22, 24].