Objective: Longer duration of untreated illness, longer duration of current episode, and the severity of medication side effects may negatively impact on the perceived disability and psychosocial impairment of patients with major affective and anxiety disorders. Studies also suggested the involvement of sensory perception in emotional and psychopathological processes. The present study aimed to examine the relationship between Sensory Processing Disorders (SPD), duration of untreated illness and current illness episode, and the severity of side effects related to psychoactive medications. Methods: The sample included 178 participants with an age ranging from 17 to 85 years (mean=53.84±15.55). Participants were diagnosed with unipolar Major Depressive Disorder (MDD) (50%), Bipolar Disorder (BD) (33.7%), and Anxiety disorders (16.3%). They completed a socio-demographic questionnaire, the Udvalg for Kliniske Undersøgelser (UKU), and Adolescent/Adult Sensory Profile (AASP) questionnaire. Results: Longer duration of current episode correlated with greater registration of sensory input and lower avoidance from sensory input among unipolar patients; with lower registration of sensory input, and higher tendency for sensory sensitivity/avoidance among bipolar participants; with lower sensory sensitivity/avoidance among anxiety participants, respectively. Also, mean UKU total scores correlated with lower sensory sensitivity among bipolar individuals. Conclusion: SPD expressed in either hypo/hyper sensitivity may serve to clinically characterize subjects with major affective and anxiety disorders.