Adjustment disorder is a mental disorder defined by a maladaptive response to a psychosocial stressor. The maladaptive response usually involves otherwise normal emotional and behavioral reactions that manifest more intensely than usual (considering contextual and cultural factors), causing marked distress, preoccupation with the stressor and its consequences, and functional impairment.

Diagnosis of adjustment disorder is common, with lifetime prevalence estimates for adults ranging from 5 to 21%. Adult women are diagnosed twice as often as men. Among children and adolescents, girls and boys are equally likely to be diagnosed with an adjustment disorder.

Adjustment disorder was introduced into the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III) in 1980.

Another name for adjustment disorder is stress response syndrome, as well as situational depression, since depression is one of the most common symptoms.

Signs of adjustment disorder include sadness, hopelessness, lack of enjoyment, crying spells, nervousness, anxiety, desperation, feeling overwhelmed and thoughts of suicide, performing poorly in school or work, among others.

Common characteristics of adjustment disorder include mild depressive symptoms, anxiety, and traumatic stress symptoms or a combination of the three. According to the DSM-5, there are six types of adjustment disorder, which are characterized by the following predominant symptoms: depressed mood, anxiety, mixed depression and anxiety, disturbance of conduct, mixed disturbance of emotions and conduct, and unspecified. However, the criteria for these symptoms are not specified in greater detail. Adjustment disorder may be acute or chronic, depending on whether it lasts more or less than six months. According to the DSM-5, if the adjustment disorder lasts less than six months, then it may be considered acute, or it may persist for a longer period if the stressor has long term consequences and it may be considered chronic. Moreover, the symptoms cannot last longer than six months after the stressor(s), or its consequences, have terminated. However, the stress-related disturbance does not only exist as an exacerbation of a pre-existing mental disorder.

Unlike major depressive disorder, adjustment disorder is caused by an outside stressor and generally resolves once the individual is able to adapt to the situation. The condition is different from anxiety disorder, which lacks the presence of a stressor, or post-traumatic stress disorder and acute stress disorder, which usually are associated with a more intense stressor.

Suicidal behavior is prominent among people with adjustment disorder of all ages, and up to one-fifth of adolescent suicide victims may have an adjustment disorder. Bronish and Hecht (1989) found that 70% of a series of patients with adjustment disorder attempted suicide immediately before their index admission and they remitted faster than a comparison group with major depression. Asnis et al. (1993) found that adjustment disorder patients report persistent ideation or suicide attempts less frequently than those diagnosed with major depression. According to a study on 82 adjustment disorder patients at a clinic, Bolu et al. (2012) found that 22 (26.8%) of these patients were admitted due to suicide attempt, consistent with previous findings. In addition, it was found that 15 of these 22 patients chose suicide methods that involved high chances of being saved. Henriksson et al. (2005) states statistically that the stressors are of one-half related to parental issues and one-third in peer issues.