Suppressed Assertiveness Linked to Worse Depression Outcomes and Relapse, Study Finds

A suppressed capacity for healthy, non-violent assertiveness may be one of the quiet forces that keeps depression going, according to a naturalistic study of psychiatric inpatients published in BMC Psychiatry. Researchers led by Reinhard Maß of the University of Hamburg and the Center for Mental Health Marienheide examined whether inhibition of what they call the Constructive Aggression Behavioral System, or CABS, is linked to how depressed patients respond to treatment and whether they stay well afterwards. Their findings, drawn from 416 inpatients diagnosed with major depressive disorder, suggest that people who enter treatment with high levels of this inhibition not only improve less during hospitalization but also face a higher risk of persistent symptoms and of being readmitted within a year. The work adds a provocative new dimension to the ongoing debate about what drives depression and how clinicians might identify patients who need closer follow-up after discharge.

The Constructive Aggression Behavioral System is a concept rooted in evolutionary psychology. It refers to an evolutionarily grounded pattern of behavior that allows individuals to assert their needs, interests, and boundaries in a non-violent and socially adaptive manner. Crucially, researchers distinguish it from destructive aggression: CABS is not about hostility, violence, or lashing out, but about the everyday ability to say no, defend personal limits, and pursue one’s own goals in socially acceptable ways. When this system is inhibited, the theory holds, people struggle to stand up for themselves, suppress legitimate anger, and accommodate others at their own expense. Over time, this chronic self-suppression has been proposed as a clinically relevant factor in emotional disorders, including depression, where feelings of helplessness, submissiveness, and unexpressed frustration are common features of the clinical picture.

To measure this construct, the team used the Aggressionshemmungs-Inventar, or AHI, a psychometric instrument designed to quantify the inhibition of constructive aggression. The study followed 416 inpatients with major depressive disorder, assessing them with the AHI and with the revised Beck Depression Inventory, the BDI-II, at two key points: admission to and discharge from inpatient treatment. The researchers then conducted three hierarchical multiple regression analyses. The first examined whether AHI scores at discharge were associated with the change in depressive symptoms from admission to discharge. The second tested whether those scores predicted depressive symptoms at six-month follow-up. The third asked whether they predicted psychiatric readmission within one year. Importantly, the analyses controlled for a range of potential confounders, including age, gender, suicidality, unemployment, comorbid anxiety, and antidepressant use, strengthening the case that the associations were not simply artifacts of these better-known risk factors.

The results were striking from the very first measurement. At admission, patients showed markedly elevated AHI scores, with a mean standardized value of 1.40, indicating substantial inhibition of constructive aggression across the group. In other words, people arriving for inpatient depression treatment were, on average, far more inhibited in their capacity for healthy assertiveness than the reference population. During the course of treatment, both depressive symptoms and AHI scores decreased significantly, suggesting that the two move together as patients recover. This parallel improvement hints at a possible coupling between the ability to assert oneself constructively and the severity of depressive symptoms, although the observational design of the study means the direction of that relationship cannot be determined with certainty.

The most consequential findings emerged from the follow-up analyses. AHI scores at discharge were associated not only with symptom change during treatment but also with depressive symptoms at the six-month follow-up and with readmission to psychiatric care within one year. Patients who left the hospital still highly inhibited in their constructive aggression were more likely to remain symptomatic and to end up back on the ward. Because the regression models adjusted for suicidality, unemployment, comorbid anxiety, antidepressant use, and demographic variables, the association appears to carry prognostic information beyond what these established risk factors capture. If replicated, this would make CABS inhibition a candidate transdiagnostic marker, one that could help clinicians flag depressed patients who need intensified aftercare, closer monitoring, or targeted psychotherapeutic work on assertiveness and boundary-setting.

Why might suppressed assertiveness matter so much for depression? Several theoretical threads converge on an answer. Evolutionary accounts suggest that the capacity to defend one’s interests is a fundamental behavioral adaptation; when it is chronically blocked, individuals may experience persistent frustration, powerlessness, and social defeat, all of which are known to be linked to depressive states. From a clinical perspective, patients who cannot say no or articulate their needs may remain locked in stressful interpersonal dynamics that continuously reinforce feelings of worthlessness and hopelessness. Standard antidepressant treatment, whether pharmacological or psychotherapeutic, does not always address this underlying pattern. The study’s authors frame CABS inhibition as a potentially transdiagnostic construct, meaning it may cut across diagnostic categories such as depression and anxiety rather than being specific to any single disorder, which would explain why it correlates with outcomes even after accounting for comorbid anxiety.

The authors are careful about what their data can and cannot show. Because the study is observational and naturalistic, meaning patients received routine clinical care rather than an experimental intervention, the results do not allow conclusions about causal effects. It remains possible that CABS inhibition is a consequence of depression rather than a contributor to it, or that a third factor drives both. Depressed patients may simply find it harder to assert themselves, and lingering inhibition at discharge may reflect residual illness rather than an independent risk factor. The researchers explicitly call for future longitudinal and experimental studies to examine whether changes in CABS inhibition are associated with changes in clinical outcomes, and to clarify the construct’s potential role in the onset and maintenance of emotional disorders. Only such studies, ideally with interventions designed to reduce constructive aggression inhibition, could establish whether targeting it improves recovery.

Even with those caveats, the practical implications are considerable. Depression remains one of the world’s most burdensome conditions, and readmission within a year of discharge is a persistent problem for psychiatric services. A simple, validated questionnaire such as the AHI could, in principle, be administered at discharge at negligible cost, offering clinicians an additional signal about who is at risk of relapse. If subsequent research confirms the predictive value of CABS inhibition, therapeutic modules aimed at strengthening constructive assertiveness, teaching patients to express needs and set boundaries without aggression, could be integrated into inpatient programs and aftercare planning. Such approaches would complement, not replace, existing treatments, but they might address a dimension of the illness that current protocols often overlook.

The study also speaks to a broader shift in psychiatric research away from purely symptom-based models and toward transdiagnostic mechanisms, traits, and behaviors that cut across diagnostic boundaries. Constructs like CABS inhibition sit at the intersection of evolutionary psychology, behavioral neuroscience, and clinical psychopathology, and they invite researchers to ask not only what is wrong in depression but what adaptive capacities have been suppressed. The Hamburg and Marienheide team’s work, conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of the Medical Association of Nordrhein, with written informed consent from all participants, offers a carefully controlled first step in that direction. Whether reducing the inhibition of constructive aggression proves to be a lever for better recovery will depend on the experimental and longitudinal studies the authors now call for, but the message of this naturalistic study is already clear: the ability to stand up for oneself, calmly and without hostility, may matter far more for mental health than psychiatry has traditionally assumed.

Subject of Research: The association between inhibition of the Constructive Aggression Behavioral System and treatment outcomes in major depressive disorder

Article Title: Inhibition of the Constructive Aggression Behavioral System (CABS) is associated with poor short- and long-term treatment outcomes and readmission among patients with major depression: a naturalistic study

Article References: Maß, R., Backhaus, K., Pütz, K., & Szelies, M. (2026). Inhibition of the Constructive Aggression Behavioral System (CABS) is associated with poor short- and long-term treatment outcomes and readmission among patients with major depression: a naturalistic study. BMC Psychiatry, 26(1), Article 720. https://doi.org/10.1186/s12888-026-08490-3

Image Credits: AI Generated

DOI: 10.1186/s12888-026-08490-3

Keywords: constructive aggression, CABS, major depressive disorder, AHI, depression treatment outcomes, psychiatric readmission, assertiveness, transdiagnostic, evolutionary psychology, psychotherapy outcome, inhibition, prognosis