To our knowledge, this is the first study that more systematically and thoroughly investigated the effects of the experimental induction of crying on subsequent mood across several time points. The most important finding was that the participants who cried reported an increase in NA immediately after their crying as well as subsequent decreases in NA at follow up (i.e., 20 and 90 min post film) in comparison to the measurement immediately after the film and also when compared to the pre-film baseline measurement (only in the case of 90 min post film). In contrast, non-criers did not experience any mood changes after the film presentation. Thus, the present results seem to reconcile the findings of previous quasi-experimental studies of crying (i.e., that crying predominantly results in an increase in NA immediately after the films) and of retrospective studies (i.e., that crying can facilitate mood improvement). This is the first study that has demonstrated a clear relation between experimentally induced crying and subsequent, more long-term mood improvement. Regarding the hypothesized dose–response relationship, frequency of crying did not have any predictive power when only the crying participants were taken into account. Irrespective of how often the participants cried, the immediate decreases as well as subsequent increases in their mood were rather similar.

Perhaps it is in particular the strong mood improvement experienced by those participants who cried that fuels the popular notion that crying brings relief. It is obvious that decreases in NA from T2 to T4 and from T3 to T4 in participants who cried are mainly the consequences of previous (i.e., T1–T2) NA increases, that is, the return to baseline levels. This finding may explain why people report mood improvement after crying: those who cried indeed experience greater mood changes, be it after an initial deterioration. Such strong mood recovery, as well as the observed return of NA even to below baseline levels thus seems to support the hypothesis about the cathartic effects of crying. These findings are in accordance with both of our hypotheses about the negative effects of crying over the short run and about mood increases that follow crying over the longer run. On a more general level, these findings can be compared to the short-term negative and long-term positive effects of the expression of emotion on mood and well-being (Pennebaker 1997; Smyth 1998). However, the question remains whether these long-term mood-enhancing effects of crying and of other types of emotion expression are mediated by the same cognitive, physiological, or behavioral mechanisms.

One could argue that the observed general decline in NA reported by criers at the final measurement is the consequence of increased tension and nervousness of the study participants at the beginning of the experiment, due to the fact that they are in a new and uncertain situation, rather than being the result of crying. However, if this mood improvement is considered as a kind of return to the (pre-experiment) baseline level, it remains unclear why non-criers did not end up with improved mood at the final relative to the first measurement. Also note that both groups did not differ in NA at T1.

If the observed decline in NA below the baseline level reflects the real effects of crying, which physiological mechanisms could account for such finding? The most likely candidates are increases in parasympathetic activation and increases in levels of oxytocin, which may accompany specific cognitive and behavioral mechanisms (see Gračanin et al. 2014). For example, there is mounting evidence that crying is accompanied with and possibly followed by increases in parasympathetic activation (e.g., Hendriks et al. 2007; Rottenberg et al. 2003), which is also related to states of relaxation and absence of intensive negative emotion (Porges 2003). In addition, increases in oxytocin are thought to accompany crying, resulting not only from comforting behaviors that are elicited by crying, but also from behavioural and cognitive mechanisms that are not necessarily based on the reception of social support (Vingerhoets 2013; Gračanin et al. 2014). Since there is some evidence that low oxytocin is related to sadness (Turner et al. 1999), one could speculate that increases in the level of this hormone following crying could lead to associated decreases in NA. On the other hand, a much simpler explanation is that the decreased mood stimulates the participants to apply all kinds of cognitive and behavioral mood management strategies, which would result in the desired mood improvement, without any necessary influence of the here suggested, direct physiological and cognitive mechanisms, induced by the act of crying. However, after partializing out the effect of change in NA from T1 to T2, the observed decrease in NA remained significant. Thus, the amount of initial NA increase, that could have motivated participants to engage in mood enhancing behaviors, was not related to general mood improvement. The stability of this effect after excluding the effects of initial mood deterioration also contrasts the possibility that criers ended up with increased mood because they were generally more emotionally reactive, since the initial increase in NA did not seem to affect the mood improvement at the delayed measurement as compared to the measurement before crying.

Two aspects of this study were innovative. First, mood was assessed at three fixed times after having been exposed to an emotional film. Although the time of the initial crying episodes varied across participants, this variation was relatively small, and, more importantly, the time of the last crying episode was fixed. Second, objectively established crying was operationalized both in terms of mere appearance as well as in terms of frequency. The relatively high number of participants and the optimal ratio of criers to non-criers represent strong features of the study as well. On the other hand, we have to keep in mind that the present study, being similar to previous laboratory studies, also necessarily had a quasi-experimental design, meaning that participants were assigned to the two groups on the basis of their responses to the films. It thus cannot be excluded that individuals who did and did not cry, differed in certain personality traits (Stougie et al. 2004) or other, more temporarily characteristics related to changes in crying and/or mood after the exposure to emotional stimuli (cf. Vingerhoets 2013). For example, previous research has shown that more neurotic individuals cry more often (De Fruyt 1997) and more easily (Peter et al. 2001), while, for example, introverted and depressive individuals report more often the absence of mood benefits following crying (De Fruyt 1997; Rottenberg et al. 2008b). Kraemer and Hastrup (1988) tried to solve this issue of confounding individual differences by instructing participants to cry or to suppress their tears, but, as noted above, the adequacy of that solution is arguable because such a manipulation makes the situation rather artificial. Bylsma et al. (2011) applied a diary methodology in order to separate inter-individual from intra-individual differences in mood that follows crying. They showed that crying is related to increased negative mood even the day after the crying episode. Although this method has a high ecological validity, it still does not exclude the non-systematic effects of different conditions that inflict both crying and negative mood during the periods of several days. It is possible that both crying and mood dynamics observed in our as well as the latter study are influenced by some temperamental characteristics, such as emotional reactivity (Larsen and Diener 1987), despite the above presented preliminary findings which seem to challenge such an explanation. Relatedly, distinct mood dynamics of criers and non-criers in our study could be interpreted in the context of previous research showing a positive relation between emotion suppression and vulnerability to mood disturbances (Ehring et al. 2010).

A final critical and still unanswered question is whether the observed decreased NA really reflects a different mood state, induced by the crying, or that it reflects a kind of response shift, a phenomenon, which is well-known in the literature on quality of life in cancer patients. Repeatedly it has been found that cancer patients report a better quality of life than before their disease, when comparing their absolute scores on quality-of-life measures. However, when being asked to compare directly their current quality of life with before their disease (as is also done in retrospective studies on mood changes after crying), they indicate unanimously that their current state is worse than before their disease (Schwartz and Sprangers 1999). This response shift might be the result of changes in internal standards, conceptualization of the concepts, and/or one’s values. This methodological issue certainly needs adequate consideration in future studies, for example by including a measure asking participants to compare directly their current mood state to the pre-film measurement. For future studies, we also suggest to pay an additional attention to factors that influence the memory of emotional events and mood, to stable individual differences related to affect intensity and variability, as well as to mood regulation processes.

In conclusion, the present findings suggest a simple, obvious, and parsimonious explanation for the paradoxical findings of different studies investigating the effects of crying on mood. After the initial deterioration of mood following crying that is usually observed in laboratory studies, it takes some time for the mood, not just to recover, but also to increase above the levels that it had before the emotional event, a pattern of findings which corresponds to the results of retrospective studies.